NDS. National Design Specification for Wood Construction 2015 EDITION

NDS National Design Specification for Wood Construction 2015 EDITION ANSI/AWC NDS-2015 Approval date September 30, 2014

Updates and Errata While every precaution has been taken to ensure the accuracy of this document, errors may have occurred during development. Updates or Errata are posted to the American Wood Council website at www.awc.org. Technical inquiries may be addressed to info@awc.org. The American Wood Council (AWC) is the voice of North American traditional and engineered wood products. From a renewable resource that absorbs and sequesters carbon, the wood products industry makes products that are essential to everyday life. AWC s engineers, technologists, scientists, and building code experts develop state-of-the-art engineering data, technology, and standards on structural wood products for use by design professionals, building officials, and wood products manufacturers to assure the safe and efficient design and use of wood structural components.

NDS National Design Specification for Wood Construction 2015 EDITION Copyright 2014 American Wood Council ANSI/AWC NDS-2015 Approval date September 30, 2014

ii NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION National Design Specification (NDS) for Wood Construction 2015 Edition First Web Version: November 2014 978-1-940383-05-7 Copyright 2014 by American Wood Council All rights reserved. No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including, without limitation, electronic, optical, or mechanical means (by way of example and not limitation, photocopying, or recording by or in an information storage retrieval system) without express written permission of the American Wood Council. For information on permission to copy material, please contact: Copyright Permission American Wood Council 222 Catoctin Circle, SE, Suite 201 Leesburg, VA 20175 info@awc.org

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION iii FOREWORD The National Design Specification for Wood Construction (NDS ) was first issued by the National Lumber Manufacturers Association (now the American Wood Council) (AWC) in 1944, under the title National Design Specification for Stress-Grade Lumber and Its Fastenings. By 1971, the scope of the Specification had broadened to include additional wood products. In 1977, the title was changed to reflect the new nature of the Specification, and the content was rearranged to simplify its use. The 1991 edition was reorganized in an easier to use equation format, and many sections were rewritten to provide greater clarity. In 1992, the American Forest & Paper Association (AF&PA) formerly the National Forest Products Association was accredited as a canvass sponsor by the American National Standards Institute (ANSI). The Specification subsequently gained approval as an American National Standard designated ANSI/NF o PA NDS-1991 with an approval date of October 16, 1992. In 2010, AWC was separately incorporated, rechartered, and accredited by ANSI as a standards developing organization. The current edition of the Standard is designated ANSI/AWC NDS-2015 with an approval date of September 30, 2014. In developing the provisions of this Specification, the most reliable data available from laboratory tests and experience with structures in service have been carefully analyzed and evaluated for the purpose of providing, in convenient form, a national standard of practice. It is intended that this Specification be used in conjunction with competent engineering design, accurate fabrication, and adequate supervision of construction. Particular attention is directed to Section 2.1.2, relating to the designer s responsibility to make adjustments for particular end uses of structures. Since the first edition of the NDS in 1944, the Association s Technical Advisory Committee has continued to study and evaluate new data and developments in wood design. Subsequent editions of the Specification have included appropriate revisions to provide for use of such new information. This edition incorporates numerous changes considered by AWC s ANSI-accredited Wood Design Standards Committee. The contributions of members of this Committee to improvement of the Specification as a national design standard for wood construction are especially recognized. Acknowledgement is also made to the Forest Products Laboratory, U.S. Department of Agriculture, for data and publications generously made available, and to the engineers, scientists, and other users who have suggested changes in the content of the Specification. AWC invites and welcomes comments, inquiries, suggestions, and new data relative to the provisions of this document. It is intended that this document be used in conjunction with competent engineering design, accurate fabrication, and adequate supervision of construction. AWC does not assume any responsibility for errors or omissions in the document, nor for engineering designs, plans, or construction prepared from it. Those using this standard assume all liability arising from its use. The design of engineered structures is within the scope of expertise of licensed engineers, architects, or other licensed professionals for applications to a particular structure. American Wood Council

iv NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION v TABLE OF CONTENTS Part/Title Page Part/Title Page 1 General Requirements for Structural Design...1 1.1 Scope 2 1.2 General Requirements 2 1.3 Standard as a Whole 2 1.4 Design Procedures 2 1.5 Specifications and Plans 3 1.6 Notation 3 2 Design Values for Structural Members...9 2.1 General 10 2.2 Reference Design Values 10 2.3 Adjustment of Reference Design Values 10 3 Design Provisions and Equations...13 3.1 General 14 3.2 Bending Members General 15 3.3 Bending Members Flexure 15 3.4 Bending Members Shear 17 3.5 Bending Members Deflection 19 3.6 Compression Members General 20 3.7 Solid Columns 21 3.8 Tension Members 22 3.9 Combined Bending and Axial Loading 22 3.10 Design for Bearing 23 4 Sawn Lumber...25 4.1 General 26 4.2 Reference Design Values 27 4.3 Adjustment of Reference Design Values 28 4.4 Special Design Considerations 31 5 Structural Glued Laminated Timber...33 5.1 General 34 5.2 Reference Design Values 35 5.3 Adjustment of Reference Design Values 36 5.4 Special Design Considerations 39 6 Round Timber Poles and Piles...43 6.1 General 44 6.2 Reference Design Values 44 6.3 Adjustment of Reference Design Values 44 7 Prefabricated Wood I-Joists...47 7.1 General 48 7.2 Reference Design Values 48 7.3 Adjustment of Reference Design Values 48 7.4 Special Design Considerations 50 8 Structural Composite Lumber...51 8.1 General 52 8.2 Reference Design Values 52 8.3 Adjustment of Reference Design Values 52 8.4 Special Design Considerations 54 9 Wood Structural Panels...55 9.1 General 56 9.2 Reference Design Values 56 9.3 Adjustment of Reference Design Values 57 9.4 Design Considerations 58 10 Cross-Laminated Timber...59 10.1 General 60 10.2 Reference Design Values 60 10.3 Adjustment of Reference Design Values 60 10.4 Special Design Considerations 62 11 Mechanical Connections...63 11.1 General 64 11.2 Reference Design Values 65 11.3 Adjustment of Reference Design Values 65 12 Dowel-Type Fasteners...73 12.1 General 74 12.2 Reference Withdrawal Design Values 76 12.3 Reference Lateral Design Values 80 12.4 Combined Lateral and Withdrawal Loads 86 12.5 Adjustment of Reference Design Values 86 12.6 Multiple Fasteners 90 13 Split Ring and Shear Plate Connectors...117 13.1 General 118 13.2 Reference Design Values 119 13.3 Placement of Split Ring and Shear Plate Connectors 125 14 Timber Rivets...131 14.1 General 132 14.2 Reference Design Values 132 14.3 Placement of Timber Rivets 134

vi TABLE OF CONTENTS Part/Title Pag Part/Title Page 15 Special Loading Conditions...143 15.1 Lateral Distribution of a Concentrated Load 144 15.2 Spaced Columns 144 15.3 Built-Up Columns 146 15.4 Wood Columns with Side Loads and Eccentricity 149 16 Fire Design of Wood Members...151 16.1 General 152 16.2 Design Procedures for Exposed Wood Members 152 16.3 Wood Connections 154 Appendix...155 Appendix A (Non-mandatory) Construction and Design Practices 156 Appendix B (Non-mandatory) Load Duration (ASD Only) 158 Appendix C (Non-mandatory) Temperature Effects 160 Appendix D (Non-mandatory) Lateral Stability of Beams 161 Appendix E (Non-mandatory) Local Stresses in Fastener Groups 162 Appendix F (Non-mandatory) Design for Creep and Critical Deflection Applications 167 Appendix G (Non-mandatory) Effective Column Length 169 Appendix H (Non-mandatory) Lateral Stability of Columns 170 Appendix I (Non-mandatory) Yield Limit Equations for Connections 171 Appendix J (Non-mandatory) Solution of Hankinson Formula 174 Appendix K (Non-mandatory) Typical Dimensions for Split Ring and Shear Plate Connectors 177 Appendix L (Non-mandatory) Typical Dimensions for Dowel-Type Fasteners and Washers 178 Appendix M (Non-mandatory) Manufacturing Tolerances for Rivets and Steel Side Plates for Timber Rivet Connections 182 Appendix N (Mandatory) Load and Resistance Factor Design (LRFD) 183 References...185

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION vii LIST OF TABLES 2.3.2 Frequently Used Load Duration Factors, C D... 11 2.3.3 Temperature Factor, C t... 11 2.3.5 Format Conversion Factor, K F (LRFD Only)... 12 2.3.6 Resistance Factor, φ (LRFD Only)... 12 3.3.3 Effective Length, e, for Bending Members... 16 3.10.4 Bearing Area Factors, C b... 24 4.3.1 Applicability of Adjustment Factors for Sawn Lumber... 29 4.3.8 Incising Factors, C i... 30 5.1.3 Net Finished Widths of Structural Glued Laminated Timbers... 34 5.2.8 Radial Tension Design Factors, F rt, for Curved Members... 36 5.3.1 Applicability of Adjustment Factors for Structural Glued Laminated Timber... 37 6.3.1 Applicability of Adjustment Factors for Round Timber Poles and Piles... 45 6.3.5 Condition Treatment Factor, C ct... 45 6.3.11 Load Sharing Factor, C ls, per ASTM D 2899... 46 7.3.1 Applicability of Adjustment Factors for Prefabricated Wood I-Joists... 49 8.3.1 Applicability of Adjustment Factors for Structural Composite Lumber... 53 9.3.1 Applicability of Adjustment Factors for Wood Structural Panels... 57 9.3.4 Panel Size Factor, C s... 58 10.3.1 Applicability of Adjustment Factors for Cross-Laminated Timber... 61 10.4.1.1 Shear Deformation Adjustment Factors, K s... 62 11.3.1 Applicability of Adjustment Factors for Connections... 66 11.3.3 Wet Service Factors, C M, for Connections... 67 11.3.4 Temperature Factors, C t, for Connections... 67 11.3.6A Group Action Factors, C g, for Bolt or Lag Screw Connections with Wood Side Members... 70 11.3.6B 11.3.6C 11.3.6D Group Action Factors, C g, for 4" Split Ring or Shear Plate Connectors with Wood Side Members... 70 Group Action Factors, C g, for Bolt or Lag Screw Connections with Steel Side Plates... 71 Group Action Factors, C g, for 4" Shear Plate Connectors with Steel Side Plates... 72 12.2A Lag Screw Reference Withdrawal Design Values, W... 77 12.2B Cut Thread or Rolled Thread Wood Screw Reference Withdrawal Design Values, W... 78 12.2C Nail and Spike Reference Withdrawal Design Values, W... 79 12.2D Post-Frame Ring Shank Nail Reference Withdrawal Design Values, W... 80 12.3.1A Yield Limit Equations... 81 12.3.1B Reduction Term, R d... 81 12.3.3 Dowel Bearing Strengths, F e, for Dowel- Type Fasteners in Wood Members... 83 12.3.3A Assigned Specific Gravities... 84 12.3.3B Dowel Bearing Strengths for Wood Structural Panels... 85 12.5.1A End Distance Requirements... 87 12.5.1B Spacing Requirements for Fasteners in a Row... 87 12.5.1C Edge Distance Requirements... 88 12.5.1D Spacing Requirements Between Rows... 88 12.5.1E 12.5.1F 12.5.1G Edge and End Distance and Spacing Requirements for Lag Screws Loaded in Withdrawal and Not Loaded Laterally... 88 Perpendicular to Grain Distance Requirements for Outermost Fasteners in Structural Glued Laminated Timber Members... 88 End Distance, Edge Distance and Fastener Spacing Requirements in Narrow Edge of Cross-Laminated Timber... 89 BOLTS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections for sawn lumber or SCL with both members of identical specific gravity... 92 12A

viii LIST OF TABLES 12B 12C 12D 12E 12F 12G 12H 12I 12J 12K BOLTS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections for sawn lumber or SCL main member with 1/4" ASTM A 36 steel side plate... 94 BOLTS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections for structural glued laminated timber main member with sawn lumber side member of identical specific gravity... 95 BOLTS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections for structural glued laminated timber main member with 1/4" ASTM A 36 steel side plate... 96 BOLTS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections for sawn lumber or SCL to concrete... 97 BOLTS: Reference Lateral Design Values, Z, for Double Shear (three member) Connections for sawn lumber or SCL with all members of identical specific gravity... 98 BOLTS: Reference Lateral Design Values, Z, for Double Shear (three member) Connections for sawn lumber or SCL main member with 1/4" ASTM A 36 steel side plates... 100 BOLTS: Reference Lateral Design Values, Z, for Double Shear (three member) Connections for structural glued laminated timber main member with sawn lumber side members of identical specific gravity..101 BOLTS: Reference Lateral Design Values, Z, for Double Shear (three member) Connections for structural glued laminated timber main member with 1/4" ASTM A 36 steel side plates... 102 LAG SCREWS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections for sawn lumber or SCL with both members of identical specific gravity... 104 LAG SCREWS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections for sawn lumber or SCL with ASTM A653, Grade 33 steel side plate (for t s <1/4") or ASTM A 36 steel side plate (for t s =1/4")... 106 12L 12M 12N 12P 12Q 12R 12S 12T 13A WOOD SCREWS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections for sawn lumber or SCL with both members of identical specific gravity... 107 WOOD SCREWS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections for sawn lumber or SCL with ASTM 653, Grade 33 steel side plate... 108 COMMON, BOX, or SINKER STEEL WIRE NAILS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections for sawn lumber or SCL with both members of identical specific gravity... 109 COMMON, BOX, or SINKER STEEL WIRE NAILS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections for sawn lumber or SCL with ASTM 653, Grade 33 steel side plate... 110 COMMON, BOX, or SINKER STEEL WIRE NAILS: Reference Lateral Design Values (Z) for Single Shear (two member) Connections for sawn lumber or SCL with wood structural panel side members with an effective G=0.50... 112 COMMON, BOX, or SINKER STEEL WIRE NAILS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections with wood structural panel side members with an effective G=0.42... 113 POST FRAME RING SHANK NAILS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections for sawn lumber or SCL with both members of identical specific gravity... 114 POST FRAME RING SHANK NAILS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections for sawn lumber or SCL with ASTM A653, Grade 33 steel side plates... 115 Species Groups for Split Ring and Shear Plate Connectors... 119 13.2A Split Ring Connector Unit Reference Design Values... 120

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION ix 13.2B Shear Plate Connector Unit Reference Design Values... 121 13.2.3 Penetration Depth Factors, C d, for Split Ring and Shear Plate Connectors Used with Lag Screws... 122 13.2.4 Metal Side Plate Factors, C st, for 4" Shear Plate Connectors Loaded Parallel to Grain... 122 13.3.2.2 Factors for Determining Minimum Spacing Along Connector Axis for C = 1.0... 126 13.3.3.1-1 Factors for Determining Minimum Spacing Along Axis of Cut of Sloping Surfaces... 127 13.3.3.1-2 Factors for Determining Minimum Loaded Edge Distance for Connectors in End Grain... 127 13.3.3.1-3 Factors for Determining Minimum Unloaded Edge Distance Parallel to Axis of Cut... 128 13.3.3.1-4 Factors for Determining Minimum End Distance Parallel to Axis of Cut... 128 13.3 Geometry Factors, C, for Split Ring and Shear Plate Connectors... 129 14.2.3 Metal Side Plate Factor, C st, for Timber Rivet Connections... 133 14.3.2 Minimum End and Edge Distances for Timber Rivet Joints... 134 14.2.1A 14.2.1B 14.2.1C 14.2.1D Reference Wood Capacity Design Values Parallel to Grain, P w, for Timber Rivets (Rivet Length = 1-1/2" s p = 1" s q = 1")... 135 Reference Wood Capacity Design Values Parallel to Grain, P w, for Timber Rivets (Rivet Length = 1-1/2" s p = 1-1/2" s q = 1")... 136 Reference Wood Capacity Design Values Parallel to Grain, P w, for Timber Rivets (Rivet Length = 2-1/2" s p = 1" s q = 1")... 137 Reference Wood Capacity Design Values Parallel to Grain, P w, for Timber Rivets (Rivet Length = 2-1/2" s p = 1-1/2" s q = 1")... 138 14.2.1E 14.2.1F 14.2.2A 14.2.2B Reference Wood Capacity Design Values Parallel to Grain, P w, for Timber Rivets (Rivet Length = 3-1/2" s p = 1" s q = 1")... 139 Reference Wood Capacity Design Values Parallel to Grain, P w, for Timber Rivets (Rivet Length = 3-1/2" s p = 1-1/2" s q = 1")... 140 Values of q w (lbs) Perpendicular to Grain for Timber Rivets... 141 Geometry Factor, C, for Timber Rivet Connections Loaded Perpendicular to Grain... 141 15.1.1 Lateral Distribution Factors for Moment.. 144 15.1.2 Lateral Distribution in Terms of Proportion of Total Load... 144 16.2.1A 16.2.1B Effective Char Rates and Char Depths (for β n = 1.5 in./hr.)... 152 Effective Char Depths (for CLT with β n = 1.5 in./hr.)... 153 16.2.2 Adjustment Factors for Fire Design... 154 F1 Coefficients of Variation in Modulus of Elasticity (COV E ) for Lumber and Structural Glued Laminated Timber... 167 G1 Buckling Length Coefficients, K e... 169 I1 Fastener Bending Yield Strengths, F yb... 173 L1 to L6 (Non-mandatory) Typical Dimensions for Dowel-Type Fasteners and Washers: N1 L1 Standard Hex Bolts... 178 L2 Standard Hex Lag Screws... 179 L3 Standard Wood Screws... 180 L4 Standard Common, Box, and Sinker Steel Wire Nails... 180 L5 Post-Frame Ring Shank Nails... 181 L6 Standard Cut Washers... 181 Format Conversion Factor, K F (LRFD Only)... 184 N2 Resistance Factor, φ (LRFD Only)... 184 N3 Time Effect Factor, λ (LRFD Only)... 184

x LIST OF FIGURES LIST OF FIGURES 3A Spacing of Staggered Fasteners... 14 3B Net Cross Section at a Split Ring or Shear Plate Connection... 14 3C Shear at Supports... 17 3D 3E Bending Member End-Notched on Compression Face... 18 Effective Depth, d e, of Members at Connections... 19 3F Simple Solid Column... 20 3G Combined Bending and Axial Tension... 22 3H Combined Bending and Axial Compression... 23 3I Bearing at an Angle to Grain... 24 4A Notch Limitations for Sawn Lumber Beams... 32 5A Axis Orientations... 35 5B Depth, d y, for Flat Use Factor... 38 5C Double-Tapered Curved Bending Member... 40 5D Tudor Arch... 41 5E Tapered Straight Bending Members... 41 11A Eccentric Connections... 64 11B Group Action for Staggered Fasteners... 69 12A Toe-Nail Connection... 75 12B Single Shear Bolted Connections... 82 12C Double Shear Bolted Connections... 82 12D Multiple Shear Bolted Connections... 85 12E Shear Area for Bolted Connections... 85 12F Combined Lateral and Withdrawal Loading... 86 12G Bolted Connection Geometry... 87 12H Spacing Between Outer Rows of Bolts... 89 12I End Distance, Edge Distance and Fastener Spacing Requirements in Narrow Edge of Cross-Laminated Timber... 89 13A Split Ring Connector... 118 13B Pressed Steel Shear Plate Connector... 118 13C Malleable Iron Shear Plate Connector... 118 13D Axis of Cut for Symmetrical Sloping End Cut... 123 13E Axis of Cut for Asymmetrical Sloping End Cut... 123 13F Square End Cut... 124 13G Sloping End Cut with Load Parallel to Axis of Cut (ϕ = 0 )... 124 13H Sloping End Cut with Load Perpendicular to Axis of Cut (ϕ = 90 )... 124 13I Sloping End Cut with Load at an Angle ϕ to Axis of Cut... 124 13J Connection Geometry for Split Rings and Shear Plates... 125 13K End Distance for Members with Sloping End Cut... 125 13L Connector Axis and Load Angle... 125 14A End and Edge Distance Requirements for Timber Rivet Joints... 134 15A Spaced Column Joined by Split Ring or Shear Plate Connectors... 145 15B Mechanically Laminated Built-Up Columns... 147 15C Typical Nailing Schedules for Built-Up Columns... 148 15D Typical Bolting Schedules for Built-Up Columns... 148 15E Eccentrically Loaded Column... 150 B1 Load Duration Factors, C D, for Various Load Durations... 159 E1 Staggered Rows of Bolts... 163 E2 Single Row of Bolts... 164 E3 Single Row of Split Ring Connectors... 165 E4 A critical for Split Ring Connection (based on distance from end of member)... 165 E5 A critical for Split Ring Connection (based on distance between first and second split ring)... 166 I1 (Non-mandatory) Connection Yield Modes... 172 J1 Solution of Hankinson Formula... 176 J2 Connection Loaded at an Angle to Grain... 176

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 1 1 GENERAL REQUIREMENTS FOR STRUCTURAL DESIGN 1.1 Scope 2 1.2 General Requirements 2 1.3 Standard as a Whole 2 1.4 Design Procedures 2 1.5 Specifications and Plans 3 1.6 Notation 3

2 GENERAL REQUIREMENTS FOR STRUCTURAL DESIGN 1.1 Scope 1.1.1 Practice Defined 1.1.1.1 This Specification defines the methods to be followed in structural design with the following wood products: - visually graded lumber - mechanically graded lumber - structural glued laminated timber - timber piles - timber poles - prefabricated wood I-joists - structural composite lumber - wood structural panels - cross-laminated timber It also defines the practice to be followed in the design and fabrication of single and multiple fastener connections using the fasteners described herein. 1.1.1.2 Structural assemblies utilizing panel products shall be designed in accordance with principles of engineering mechanics (see References 32, 33, 34, and 53 for design provisions for commonly used panel products). 1.1.1.3 Structural assemblies utilizing metal connector plates shall be designed in accordance with accepted engineering practice (see Reference 9). 1.1.1.4 Shear walls and diaphragms shall be designed in accordance with the Special Design Provisions for Wind and Seismic (see Reference 56). 1.1.1.5 This Specification is not intended to preclude the use of materials, assemblies, structures or designs not meeting the criteria herein, where it is demonstrated by analysis based on recognized theory, fullscale or prototype loading tests, studies of model analogues or extensive experience in use that the material, assembly, structure or design will perform satisfactorily in its intended end use. 1.1.2 Competent Supervision The reference design values, design value adjustments, and structural design provisions in this Specification are for designs made and carried out under competent supervision. 1.2 General Requirements 1.2.1 Conformance with Standards The quality of wood products and fasteners, and the design of load-supporting members and connections, shall conform to the standards specified herein. 1.2.2 Framing and Bracing All members shall be so framed, anchored, tied, and braced that they have the required strength and rigidity. Adequate bracing and bridging to resist wind and other lateral forces shall be provided. 1.3 Standard as a Whole The various Chapters, Sections, Subsections and Articles of this Specification are interdependent and, except as otherwise provided, the pertinent provisions of each Chapter, Section, Subsection, and Article shall apply to every other Chapter, Section, Subsection, and Article. 1.4 Design Procedures This Specification provides requirements for the design of wood products specified herein by the following methods: (a) Allowable Stress Design (ASD) (b) Load and Resistance Factor Design (LRFD) Designs shall be made according to the provisions for Allowable Stress Design (ASD) or Load and Resistance Factor Design (LRFD). 1.4.1 Loading Assumptions Wood buildings or other wood structures, and their structural members, shall be designed and constructed to safely support all anticipated loads. This Specification is predicated on the principle that the loading assumed in the design represents actual conditions.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 3 1.4.2 Governed by Codes Minimum design loads shall be in accordance with the building code under which the structure is designed, or where applicable, other recognized minimum design load standards. 1.4.3 Loads Included Design loads include any or all of the following loads or forces: dead, live, snow, wind, earthquake, erection, and other static and dynamic forces. 1.5 Specifications and Plans 1.5.1 Sizes The plans or specifications, or both, shall indicate whether wood products sizes are stated in terms of standard nominal, standard net or special sizes, as specified for the respective wood products in Chapters 4, 5, 6, 7, 8, 9 and 10. 1.6 Notation Except where otherwise noted, the symbols used in this Specification have the following meanings: A = area of cross section, in. 2 Acritical = minimum shear area for any fastener in a row, in. 2 Aeff = effective cross-sectional area of a crosslaminated timber section, in. 2 /ft of panel width Agroup-net = critical group net section area between first and last row of fasteners, in. 2 Am = gross cross-sectional area of main member(s), in. 2 An = cross-sectional area of notched member, in. 2 Anet = net section area, in. 2 Aparallel = area of cross section of cross-laminated timber layers with fibers parallel to the load direction, in. 2 /ft of panel width As = sum of gross cross-sectional areas of side member(s), in. 2 CD = load duration factor CF = size factor for sawn lumber 1.4.4 Load Combinations Combinations of design loads and forces, and load combination factors, shall be in accordance with the building code under which the structure is designed, or where applicable, other recognized minimum design load standards (see Reference 5 for additional information). The governing building code shall be permitted to be consulted for load combination factors. Load combinations and associated time effect factors, λ, for use in LRFD are provided in Appendix N. C I = stress interaction factor for tapered glued laminated timbers CL = beam stability factor CM = wet service factor CP = column stability factor CT = buckling stiffness factor for dimension lumber CV = volume factor for structural glued laminated timber or structural composite lumber Cb = bearing area factor Cc = curvature factor for structural glued laminated timber Ccs = critical section factor for round timber piles Cct = condition treatment factor for timber poles and piles Cd = penetration depth factor for connections Cdi = diaphragm factor for nailed connections Cdt = empirical constant derived from relationship of equations for deflection of tapered straight beams and prismatic beams 1 GENERAL REQUIREMENTS FOR STRUCTURAL DESIGN

4 GENERAL REQUIREMENTS FOR STRUCTURAL DESIGN Ceg = end grain factor for connections Cfu = flat use factor Cg = group action factor for connections Ci = incising factor for dimension lumber Cls = load sharing factor for timber piles Cr = repetitive member factor for dimension lumber, prefabricated wood I-joists, and structural composite lumber Crs = empirical load-shape radial stress reduction factor for double-tapered curved structural glued laminated timber bending members Cs = wood structural panel size factor Cst = metal side plate factor for 4" shear plate connections Ct = temperature factor Ctn = toe-nail factor for nailed connections Cvr = shear reduction factor for structural glued laminated timber Cy = tapered structural glued laminated timber beam deflection factor C = geometry factor for connections COVE = coefficient of variation for modulus of elasticity D = dowel-type fastener diameter, in. Dr = dowel-type fastener root diameter, in. E = length of tapered tip of a driven fastener, in. E, E' = reference and adjusted modulus of elasticity, psi Eaxial = modulus of elasticity of structural glued laminated timber for extensional deformations, psi Emin, Emin' = reference and adjusted modulus of elasticity for beam stability and column stability calculations, psi (EI)min, (EI)min' = reference and adjusted EI for beam stability and column stability calculations, psi (EI)app, (EI)app' = reference and adjusted apparent bending stiffness of cross-laminated timber including shear deflection, lbs-in. 2 /ft of panel width (EI)app-min, (EI)app-min' = reference and adjusted apparent bending stiffness of cross-laminated timber for panel buckling stability calculations, lbsin. 2 /ft of panel width Em = modulus of elasticity of main member, psi Es = modulus of elasticity of side member, psi Ex = modulus of elasticity of structural glued laminated timber for deflections due to bending about the x-x axis, psi Ex min = modulus of elasticity of structural glued laminated timber for beam and column stability calculations for buckling about the x-x axis, psi Ey = modulus of elasticity of structural glued laminated timber for deflections due to bending about the y-y axis, psi Ey min = modulus of elasticity of structural glued laminated timber for beam and column stability calculations for buckling about the y-y axis, psi Fb, Fb' = reference and adjusted bending design value, psi Fb* = reference bending design value multiplied by all applicable adjustment factors except CL, psi Fb** = reference bending design value multiplied by all applicable adjustment factors except CV, psi Fb1' = adjusted edgewise bending design value, psi Fb2' = adjusted flatwise bending design value, psi FbE = critical buckling design value for bending members, psi Fbx + = reference bending design value for positive bending of structural glued laminated timbers, psi Fbx - = reference bending design value for negative bending of structural glued laminated timbers, psi Fby = reference bending design value of structural glued laminated timbers bent about the y-y axis, psi Fc, Fc' = reference and adjusted compression design value parallel to grain, psi

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 5 Fc* = reference compression design value parallel to grain multiplied by all applicable adjustment factors except Cp, psi FcE = critical buckling design value for compression members, psi FcE1, FcE2 = critical buckling design value for compression member in planes of lateral support, psi Fc, Fc ' = reference and adjusted compression design value perpendicular to grain, psi Fc x = reference compression design value for bearing loads on the wide face of the laminations of structural glued laminated timber, psi Fc y = reference compression design value for bearing loads on the narrow edges of the laminations of structural glued laminated timber, psi Fe = dowel bearing strength, psi Fem = dowel bearing strength of main member, psi Fes = dowel bearing strength of side member, psi Fe = dowel bearing strength parallel to grain, psi Fe = dowel bearing strength perpendicular to grain, psi Fe = dowel bearing strength at an angle to grain, psi Frc = reference radial compression design value for curved structural glued laminated timber members, psi Frt Frt' = reference and adjusted radial tension design value perpendicular to grain for structural glued laminated timber, psi Fs, Fs' = reference and adjusted shear in the plane (rolling shear) design value for wood structural panels and cross-laminated timber, psi Ft, Ft' = reference and adjusted tension design value parallel to grain, psi Fv, Fv' = reference and adjusted shear design value parallel to grain (horizontal shear), psi Fvx = reference shear design value for structural glued laminated timber members with loads causing bending about the x-x axis, psi Fvy = reference shear design value for structural glued laminated timber members with loads causing bending about the y-y axis, psi Fyb = dowel bending yield strength of fastener, psi F ' = adjusted bearing design value at an angle to grain, psi G = specific gravity Gv = reference modulus of rigidity for wood structural panels I = moment of inertia, in. 4 I eff = effective moment of inertia of a crosslaminated timber section, in. 4 /ft of panel width (Ib/Q)eff = effective panel cross sectional shear constant of cross-laminated timber, lbs/ft of panel width K, K' = reference and adjusted shear stiffness coefficient for prefabricated wood I-joists KD = diameter coefficient for dowel-type fastener connections with D < 0.25 in. KF = format conversion factor KM = moisture content coefficient for sawn lumber truss compression chords KT = truss compression chord coefficient for sawn lumber KbE = Euler buckling coefficient for beams KcE = Euler buckling coefficient for columns Kcr = time dependent deformation (creep) factor Ke = buckling length coefficient for compression members Kf = column stability coefficient for bolted and nailed built-up columns Krs = empirical radial stress factor for doubletapered curved structural glued laminated timber bending members Ks = shear deformation adjustment factor for cross-laminated timber 1 GENERAL REQUIREMENTS FOR STRUCTURAL DESIGN Kt = temperature coefficient Kx = spaced column fixity coefficient

6 GENERAL REQUIREMENTS FOR STRUCTURAL DESIGN K = angle to grain coefficient for dowel-type fastener connections with D 0.25 in. K = empirical bending stress shape factor for double-tapered curved structural glued laminated timber L = span length of bending member, ft L = distance between points of lateral support of compression member, ft Lc = length from tip of pile to critical section, ft M = maximum bending moment, in.-lbs Mr, Mr' = reference and adjusted design moment, in.-lbs N, N' = reference and adjusted lateral design value at an angle to grain for a single split ring connector unit or shear plate connector unit, lbs P = total concentrated load or total axial load, lbs P, P' = reference and adjusted lateral design value parallel to grain for a single split ring connector unit or shear plate connector unit, lbs Pr = parallel to grain reference timber rivet capacity, lbs Pw = parallel to grain reference wood capacity for timber rivets, lbs Q = statical moment of an area about the neutral axis, in. 3 Q, Q' = reference and adjusted lateral design value perpendicular to grain for a single split ring connector unit or shear plate connector unit, lbs Qr = perpendicular to grain reference timber rivet capacity, lbs Qw = perpendicular to grain reference wood capacity for timber rivets, lbs R = radius of curvature of inside face of structural glued laminated timber member, in. RB = slenderness ratio of bending member Rd = reduction term for dowel-type fastener connections Rm = radius of curvature at center line of structural glued laminated timber member, in Rr, Rr' = reference and adjusted design reaction, lbs S = section modulus, in. 3 Seff = effective section modulus for crosslaminated timber, in 3 /ft of panel width T = temperature, F V = shear force, lbs Vr, Vr' = reference and adjusted design shear, lbs W, W' = reference and adjusted withdrawal design value for fastener, lbs per inch of penetration Z, Z' = reference and adjusted lateral design value for a single fastener connection, lbs ZGT' = adjusted group tear-out capacity of a group of fasteners, lbs ZNT' = adjusted tension capacity of net section area, lbs ZRT' = adjusted row tear-out capacity of multiple rows of fasteners, lbs ZRTi' = adjusted row tear-out capacity of a row of fasteners, lbs Z = reference lateral design value for a single dowel-type fastener connection with all wood members loaded parallel to grain, lbs Zm = reference lateral design value for a single dowel-type fastener wood-to-wood connection with main member loaded perpendicular to grain and side member loaded parallel to grain, lbs Zs = reference lateral design value for a single dowel-type fastener wood-to-wood connection with main member loaded parallel to grain and side member loaded perpendicular to grain, lbs Z = reference lateral design value for a single dowel-type fastener wood-to-wood, woodto-metal, or wood-to-concrete connection with wood member(s) loaded perpendicular to grain, lbs Z α ' = adjusted design value for dowel-type fasteners subjected to combined lateral and withdrawal loading, lbs a = support condition factor for tapered columns achar = effective char depth, in

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 7 ap = minimum end distance load parallel to grain for timber rivet joints, in. aq = minimum end distance load perpendicular to grain for timber rivet joints, in. b = breadth (thickness) of rectangular bending member, in. c = distance from neutral axis to extreme fiber, in. d = depth (width) of bending member, in. d = least dimension of rectangular compression member, in. d = pennyweight of nail or spike d = representative dimension for tapered column, in. dc = depth at peaked section of double-tapered curved structural glued laminated timber bending member, in. de = effective depth of member at a connection, in. de = depth of double-tapered curved structural glued laminated timber bending member at ends, in. de = depth at the small end of a tapered straight structural glued laminated timber bending member, in. dequiv = depth of an equivalent prismatic structural glued laminated timber member, in. dmax = the maximum dimension for that face of a tapered column, in. dmin = the minimum dimension for that face of a tapered column, in. dn = depth of member remaining at a notch measured perpendicular to the length of the member, in. dy = depth of structural glued laminated timber parallel to the wide face of the laminations when loaded in bending about the y-y axis, in. d1, d2 = cross-sectional dimensions of rectangular compression member in planes of lateral support, in. e = eccentricity, in. e = the distance the notch extends from the inner edge of the support, in. ep = minimum edge distance unloaded edge for timber rivet joints, in. eq = minimum edge distance loaded edge for timber rivet joints, in. fb = actual bending stress, psi fb1 = actual edgewise bending stress, psi fb2 = actual flatwise bending stress, psi fc = actual compression stress parallel to grain, psi fc' = concrete compressive strength, psi fc = actual compression stress perpendicular to grain, psi fr = actual radial stress in curved bending member, psi ft = actual tension stress parallel to grain, psi fv = actual shear stress parallel to grain, psi g = gauge of screw h = vertical distance from the end of the double-tapered curved structural glued laminated timber beam to mid-span, in. ha = vertical distance from the top of the double-tapered curved structural glued laminated timber supports to the beam apex, in. hlam = lamination thickness (in.) for crosslaminated timber = span length of bending member, in. = distance between points of lateral support of compression member, in. b = bearing length, in. c = clear span, in. c = length between tangent points for doubletapered curved structural glued laminated timber members, in. e = effective span length of bending member, in. e = effective length of compression member, in. e1, e2 = effective length of compression member in planes of lateral support, in. e/d = slenderness ratio of compression member m = length of dowel bearing in main member, in. n = length of notch, in. s = length of dowel bearing in side member, in. 1 GENERAL REQUIREMENTS FOR STRUCTURAL DESIGN

8 GENERAL REQUIREMENTS FOR STRUCTURAL DESIGN u = laterally unsupported span length of bending member, in. 1, 2 = distances between points of lateral support of compression member in planes 1 and 2, in. 3 = distance from center of spacer block to centroid of group of split ring or shear plate connectors in end block for a spaced column, in. m.c. = moisture content based on oven-dry weight of wood, % n = number of fasteners in a row nlam = number of laminations charred (rounded to lowest integer) for cross-laminated timber nr = number of rivet rows nc = number of rivets per row ni = number of fasteners in a row nrow = number of rows of fasteners p = length of fastener penetration into wood member, in. pmin = minimum length of fastener penetration into wood member, in. pt = length of fastener penetration into wood member for withdrawal calculations, in. r = radius of gyration, in. s = center-to-center spacing between adjacent fasteners in a row, in. scritical = minimum spacing taken as the lesser of the end distance or the spacing between fasteners in a row, in. sp = spacing between rivets parallel to grain, in. sq = spacing between rivets perpendicular to grain, in. t = thickness, in. t = exposure time, hrs. tgi = time for char front to reach glued interface (hr.) for cross-laminated timber tm = thickness of main member, in. ts = thickness of side member, in. tv = thickness for through-the-thickness shear of cross-laminated timber, in. x = distance from beam support face to load, in. H = horizontal deflection at supports of symmetrical double-tapered curved structural glued laminated timber members, in. LT = immediate deflection due to the long-term component of the design load, in. ST = deflection due to the short-term or normal component of the design load, in. T = total deflection from long-term and shortterm loading, in. c = vertical deflection at mid-span of doubletapered curved structural glued laminated timber members, in. α = angle between the wood surface and the direction of applied load for dowel-type fasteners subjected to combined lateral and withdrawal loading, degrees eff = effective char rate (in./hr.) adjusted for exposure time, t n = nominal char rate (in./hr.), linear char rate based on 1-hour exposure = load/slip modulus for a connection, lbs/in. = time effect factor = angle of taper on the compression or tension face of structural glued laminated timber members, degrees = angle between the direction of load and the direction of grain (longitudinal axis of member) for split ring or shear plate connector design, degrees = resistance factor B = angle of soffit slope at the ends of doubletapered curved structural glued laminated timber member, degrees T = angle of roof slope of double-tapered curved structural glued laminated timber member, degrees = uniformly distributed load, lbs/in.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 9 DESIGN VALUES FOR STRUCTURAL MEMBERS 2 2.1 General 10 2.2 Reference Design Values 10 2.3 Adjustment of Reference Design Values 10 Table 2.3.2 Frequently Used Load Duration Factors, C D... 11 Table 2.3.3 Temperature Factor, C t... 11 Table 2.3.5 Format Conversion Factor, K F (LRFD Only)... 12 Table 2.3.6 Resistance Factor, φ (LRFD Only)... 12

10 DESIGN VALUES FOR STRUCTURAL MEMBERS 2.1 General 2.1.1 General Requirement Each wood structural member or connection shall be of sufficient size and capacity to carry the applied loads without exceeding the adjusted design values specified herein. 2.1.1.1 For ASD, calculation of adjusted design values shall be determined using applicable ASD adjustment factors specified herein. 2.1.1.2 For LRFD, calculation of adjusted design values shall be determined using applicable LRFD adjustment factors specified herein. 2.1.2 Responsibility of Designer to Adjust for Conditions of Use Adjusted design values for wood members and connections in particular end uses shall be appropriate for the conditions under which the wood is used, taking into account the differences in wood strength properties with different moisture contents, load durations, and types of treatment. Common end use conditions are addressed in this Specification. It shall be the final responsibility of the designer to relate design assumptions and reference design values, and to make design value adjustments appropriate to the end use. 2.2 Reference Design Values Reference design values and design value adjustments for wood products in 1.1.1.1 are based on methods specified in each of the wood product chapters. Chapters 4 through 10 contain design provisions for sawn lumber, glued laminated timber, poles and piles, prefabricated wood I-joists, structural composite lumber, wood structural panels, and cross-laminated timber, respectively. Chapters 11 through 14 contain design provisions for connections. Reference design values are for normal load duration under the moisture service conditions specified. 2.3 Adjustment of Reference Design Values 2.3.1 Applicability of Adjustment Factors Reference design values shall be multiplied by all applicable adjustment factors to determine adjusted design values. The applicability of adjustment factors to sawn lumber, structural glued laminated timber, poles and piles, prefabricated wood I-joists, structural composite lumber, wood structural panels, cross-laminated timber, and connection design values is defined in 4.3, 5.3, 6.3, 7.3, 8.3, 9.3, 10.3, and 11.3, respectively. 2.3.2 Load Duration Factor, CD (ASD Only) 2.3.2.1 Wood has the property of carrying substantially greater maximum loads for short durations than for long durations of loading. Reference design values apply to normal load duration. Normal load duration represents a load that fully stresses a member to its allowable design value by the application of the full design load for a cumulative duration of approximately ten years. When the cumulative duration of the full maximum load does not exceed the specified time period, all reference design values except modulus of elasticity, E, modulus of elasticity for beam and column stability, E min, and compression perpendicular to grain, F c, based on a deformation limit (see 4.2.6) shall be multiplied by the appropriate load duration factor, C D, from Table 2.3.2 or Figure B1 (see Appendix B) to take into account the change in strength of wood with changes in load duration. 2.3.2.2 The load duration factor, C D, for the shortest duration load in a combination of loads shall apply for that load combination. All applicable load combinations shall be evaluated to determine the critical load combination. Design of structural members and connections shall be based on the critical load combination (see Appendix B.2). 2.3.2.3 The load duration factors, C D, in Table 2.3.2 and Appendix B are independent of load combination factors, and both shall be permitted to be used in design calculations (see 1.4.4 and Appendix B.4).

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 11 Table 2.3.2 Frequently Used Load Duration Factors, CD 1 2.3.5 Format Conversion Factor, KF (LRFD Only) Load Duration C D Typical Design Loads Permanent Ten years Two months Seven days Ten minutes Impact 2 0.9 1.0 1.15 1.25 1.6 2.0 Dead Load Occupancy Live Load Snow Load Construction Load Wind/Earthquake Load Impact Load 1. Load duration factors shall not apply to reference modulus of elasticity, E, reference modulus of elasticity for beam and column stability, E min, nor to reference compression perpendicular to grain design values, F c, based on a deformation limit. 2. Load duration factors greater than 1.6 shall not apply to structural members pressure-treated with water-borne preservatives (see Reference 30), or fire retardant chemicals. The impact load duration factor shall not apply to connections. 2.3.3 Temperature Factor, Ct Reference design values shall be multiplied by the temperature factors, C t, in Table 2.3.3 for structural members that will experience sustained exposure to elevated temperatures up to 150 F (see Appendix C). 2.3.4 Fire Retardant Treatment The effects of fire retardant chemical treatment on strength shall be accounted for in the design. Adjusted design values, including adjusted connection design values, for lumber and structural glued laminated timber pressure-treated with fire retardant chemicals shall be obtained from the company providing the treatment and redrying service. Load duration factors greater than 1.6 shall not apply to structural members pressure-treated with fire retardant chemicals (see Table 2.3.2). For LRFD, reference design values shall be multiplied by the format conversion factor, K F, specified in Table 2.3.5. The format conversion factor, K F, shall not apply for designs in accordance with ASD methods specified herein. 2.3.6 Resistance Factor, (LRFD Only) For LRFD, reference design values shall be multiplied by the resistance factor,, specified in Table 2.3.6. The resistance factor,, shall not apply for designs in accordance with ASD methods specified herein. 2.3.7 Time Effect Factor, (LRFD Only) For LRFD, reference design values shall be multiplied by the time effect factor,, specified in Appendix N.3.3. The time effect factor,, shall not apply for designs in accordance with ASD methods specified herein. 2 DESIGN VALUES FOR STRUCTURAL MEMBERS Table 2.3.3 Temperature Factor, Ct Reference Design Values In-Service Moisture Conditions 1 C t T100F 100F<T125F 125F<T150F F t, E, E min Wet or Dry 1.0 0.9 0.9 Dry 1.0 0.8 0.7 F b, F v, F c, and F c Wet 1.0 0.7 0.5 1. Wet and dry service conditions for sawn lumber, structural glued laminated timber, prefabricated wood I-joists, structural composite lumber, wood structural panels and cross-laminated timber are specified in 4.1.4, 5.1.4, 7.1.4, 8.1.4, 9.3.3, and 10.1.5 respectively..

12 DESIGN VALUES FOR STRUCTURAL MEMBERS Table 2.3.5 Format Conversion Factor, KF (LRFD Only) Application Property K F Member F b F t F v, F rt, F s F c F c E min 2.54 2.70 2.88 2.40 1.67 1.76 All Connections (all design values) 3.32 Table 2.3.6 Resistance Factor, (LRFD Only) Application Property Symbol Value Member F b F t F v, F rt, F s F c, F c E min b t v c s 0.85 0.80 0.75 0.90 0.85 All Connections (all design values) z 0.65

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 13 DESIGN PROVISIONS AND EQUATIONS 3 3.1 General 14 3.2 Bending Members General 15 3.3 Bending Members Flexure 15 3.4 Bending Members Shear 17 3.5 Bending Members Deflection 19 3.6 Compression Members General 20 3.7 Solid Columns 21 3.8 Tension Members 22 3.9 Combined Bending and Axial Loading 22 3.10 Design for Bearing 23 Table 3.3.3 Effective Length, e, for Bending Members... 16 Table 3.10.4 Bearing Area Factors, C b... 24

14 DESIGN PROVISIONS AND EQUATIONS 3.1 General 3.1.1 Scope Chapter 3 establishes general design provisions that apply to all wood structural members and connections covered under this Specification. Each wood structural member or connection shall be of sufficient size and capacity to carry the applied loads without exceeding the adjusted design values specified herein. Reference design values and specific design provisions applicable to particular wood products or connections are given in other Chapters of this Specification. critical section if the parallel to grain spacing between connectors in adjacent rows is less than or equal to one connector diameter (see Figure 3A). Figure 3B Net Cross Section at a Split Ring or Shear Plate Connection 3.1.2 Net Section Area 3.1.2.1 The net section area is obtained by deducting from the gross section area the projected area of all material removed by boring, grooving, dapping, notching, or other means. The net section area shall be used in calculating the load carrying capacity of a member, except as specified in 3.6.3 for columns. The effects of any eccentricity of loads applied to the member at the critical net section shall be taken into account. 3.1.2.2 For parallel to grain loading with staggered bolts, drift bolts, drift pins, or lag screws, adjacent fasteners shall be considered as occurring at the same critical section if the parallel to grain spacing between fasteners in adjacent rows is less than four fastener diameters (see Figure 3A). Figure 3A Spacing of Staggered Fasteners 3.1.3 Connections Structural members and fasteners shall be arranged symmetrically at connections, unless the bending moment induced by an unsymmetrical arrangement (such as lapped joints) has been accounted for in the design. Connections shall be designed and fabricated to insure that each individual member carries its proportional stress. 3.1.4 Time Dependent Deformations Where members of structural frames are composed of two or more layers or sections, the effect of time dependent deformations shall be accounted for in the design (see 3.5.2 and Appendix F). 3.1.5 Composite Construction 3.1.2.3 The net section area at a split ring or shear plate connection shall be determined by deducting from the gross section area the projected areas of the bolt hole and the split ring or shear plate groove within the member (see Figure 3B and Appendix K). Where split ring or shear plate connectors are staggered, adjacent connectors shall be considered as occurring at the same Composite constructions, such as wood-concrete, wood-steel, and wood-wood composites, shall be designed in accordance with principles of engineering mechanics using the adjusted design values for structural members and connections specified herein.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 15 3.2 Bending Members General 3.2.1 Span of Bending Members 3.2.3 Notches For simple, continuous and cantilevered bending members, the span shall be taken as the distance from face to face of supports, plus ½ the required bearing length at each end. 3.2.2 Lateral Distribution of Concentrated Load Lateral distribution of concentrated loads from a critically loaded bending member to adjacent parallel bending members by flooring or other cross members shall be permitted to be calculated when determining design bending moment and vertical shear force (see 15.1). 3.3 Bending Members Flexure 3.3.1 Strength in Bending The actual bending stress or moment shall not exceed the adjusted bending design value. 3.3.2 Flexural Design Equations 3.3.2.1 The actual bending stress induced by a bending moment, M, is calculated as follows: Mc M fb I S (3.3-1) For a rectangular bending member of breadth, b, and depth, d, this becomes: M 6M fb 2 S bd (3.3-2) 3.3.2.2 For solid rectangular bending members with the neutral axis perpendicular to depth at center: 3 bd I moment of inertia, in. 12 2 I bd S section modulus, in. c 6 4 3 (3.3-3) (3.3-4) 3.2.3.1 Bending members shall not be notched except as permitted by 4.4.3, 5.4.5, 7.4.4, and 8.4.1. A gradual taper cut from the reduced depth of the member to the full depth of the member in lieu of a squarecornered notch reduces stress concentrations. 3.2.3.2 The stiffness of a bending member, as determined from its cross section, is practically unaffected by a notch with the following dimensions: notch depth (1/6) (beam depth) notch length (1/3) (beam depth) 3.2.3.3 See 3.4.3 for effect of notches on shear strength. 3.3.3 Beam Stability Factor, CL 3.3.3.1 When the depth of a bending member does not exceed its breadth, d b, no lateral support is required and C L = 1.0. 3.3.3.2 When rectangular sawn lumber bending members are laterally supported in accordance with 4.4.1, C L = 1.0. 3.3.3.3 When the compression edge of a bending member is supported throughout its length to prevent lateral displacement, and the ends at points of bearing have lateral support to prevent rotation, C L = 1.0. 3.3.3.4 Where the depth of a bending member exceeds its breadth, d > b, lateral support shall be provided at points of bearing to prevent rotation. When such lateral support is provided at points of bearing, but no additional lateral support is provided throughout the length of the bending member, the unsupported length, u, is the distance between such points of end bearing, or the length of a cantilever. When a bending member is provided with lateral support to prevent rotation at intermediate points as well as at the ends, the unsupported length, u, is the distance between such points of intermediate lateral support. 3.3.3.5 The effective span length, e, for single span or cantilever bending members shall be determined in accordance with Table 3.3.3. 3 DESIGN PROVISIONS AND EQUATIONS

16 DESIGN PROVISIONS AND EQUATIONS Table 3.3.3 Effective Length, e, for Bending Members Cantilever 1 where u/d < 7 where u/d 7 Uniformly distributed load e=1.33 u e=0.90 u + 3d Concentrated load at unsupported end e=1.87 u e=1.44 u + 3d Single Span Beam 1,2 where u/d < 7 where u/d 7 Uniformly distributed load e=2.06 u e=1.63 u + 3d Concentrated load at center with no intermediate lateral support Concentrated load at center with lateral support at center Two equal concentrated loads at 1/3 points with lateral support at 1/3 points Three equal concentrated loads at 1/4 points with lateral support at 1/4 points Four equal concentrated loads at 1/5 points with lateral support at 1/5 points Five equal concentrated loads at 1/6 points with lateral support at 1/6 points Six equal concentrated loads at 1/7 points with lateral support at 1/7 points Seven or more equal concentrated loads, evenly spaced, with lateral support at points of load application Equal end moments e=1.80 u e=1.11 u e=1.68 u e=1.54 u e=1.68 u e=1.73 u e=1.78 u e=1.84 u e=1.84 u e=1.37 u + 3d 1. For single span or cantilever bending members with loading conditions not specified in Table 3.3.3: = 2.06 where e u u /d < 7 = 1.63 + 3d where 7 /d 14.3 e = 1.84 u u where e u u /d > 14.3 2. Multiple span applications shall be based on table values or engineering analysis.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 17 3.3.3.6 The slenderness ratio, R B, for bending members shall be calculated as follows: R d b e B 2 (3.3-5) 3.3.3.7 The slenderness ratio for bending members, R B, shall not exceed 50. 3.3.3.8 The beam stability factor shall be calculated as follows: * * * 1 FbE Fb 1 FbE Fb FbE Fb CL 1.9 1.9 0.95 3.4 Bending Members Shear 3.4.1 Strength in Shear Parallel to Grain (Horizontal Shear) 2 (3.3-6) 3.4.1.1 The actual shear stress parallel to grain or shear force at any cross section of the bending member shall not exceed the adjusted shear design value. A check of the strength of wood bending members in shear perpendicular to grain is not required. 3.4.1.2 The shear design procedures specified herein for calculating f v at or near points of vertical support are limited to solid flexural members such as sawn lumber, structural glued laminated timber, structural composite lumber, or mechanically laminated timber beams. Shear design at supports for built-up components containing load-bearing connections at or near points of support, such as between the web and chord of a truss, shall be based on test or other techniques. where: Fb * = reference bending design value multiplied by all applicable adjustment factors except Cfu, CV, and CL (see 2.3), psi F 3.3.3.9 See Appendix D for background information concerning beam stability calculations and Appendix F for information concerning coefficient of variation in modulus of elasticity (COV E ). 3.3.3.10 Members subjected to flexure about both principal axes (biaxial bending) shall be designed in accordance with 3.9.2. 3.4.3 Shear Design 3.4.3.1 When calculating the shear force, V, in bending members: (a) For beams supported by full bearing on one surface and loads applied to the opposite surface, uniformly distributed loads within a distance from supports equal to the depth of the bending member, d, shall be permitted to be ignored. For beams supported by full bearing on one surface and loads applied to the opposite surface, concentrated loads within a distance, d, from supports shall be permitted to be multiplied by x/d where x is the distance from the beam support face to the load (see Figure 3C). Figure 3C 1.20 E R min be 2 B Shear at Supports 3 DESIGN PROVISIONS AND EQUATIONS 3.4.2 Shear Design Equations The actual shear stress parallel to grain induced in a sawn lumber, structural glued laminated timber, structural composite lumber, or timber pole or pile bending member shall be calculated as follows: f v VQ I b (3.4-1) For a rectangular bending member of breadth, b, and depth, d, this becomes: f v 3V 2bd (3.4-2)

18 DESIGN PROVISIONS AND EQUATIONS (b) The largest single moving load shall be placed at a distance from the support equal to the depth of the bending member, keeping other loads in their normal relation and neglecting any load within a distance from a support equal to the depth of the bending member. This condition shall be checked at each support. (c) With two or more moving loads of about equal weight and in proximity, loads shall be placed in the position that produces the highest shear force, V, neglecting any load within a distance from a support equal to the depth of the bending member. 3.4.3.2 For notched bending members, shear force, V, shall be determined by principles of engineering mechanics (except those given in 3.4.3.1). (a) For bending members with rectangular cross section and notched on the tension face (see 3.2.3), the adjusted design shear, V r ', shall be calculated as follows: where: 2 dn Vr Fvbdn 3 d 2 d = depth of unnotched bending member, in. (3.4-3) dn = depth of member remaining at a notch measured perpendicular to length of member, in. stress parallel to grain nearly to that computed for an unnotched bending member with a depth of d n. (e) When a bending member is notched on the compression face at the end as shown in Figure 3D, the adjusted design shear, V r ', shall be calculated as follows: where: 2 d dn Vr Fb v d e 3 dn Figure 3D (3.4-5) e = the distance the notch extends from the inner edge of the support and must be less than or equal to the depth remaining at the notch, e dn. If e > dn, dn shall be used to calculate fv using Equation 3.4-2, in. dn = depth of member remaining at a notch meeting the provisions of 3.2.3, measured perpendicular to length of member. If the end of the beam is beveled, as shown by the dashed line in Figure 3D, dn is measured from the inner edge of the support, in. Bending Member End-Notched on Compression Face where: Fv' = adjusted shear design value parallel to grain, psi (b) For bending members with circular cross section and notched on the tension face (see 3.2.3), the adjusted design shear, V r ', shall be calculated as follows: 2 dn Vr FA v n 3 d 2 (3.4-4) An = cross-sectional area of notched member, in 2 (c) For bending members with other than rectangular or circular cross section and notched on the tension face (see 3.2.3), the adjusted design shear, V r ', shall be based on conventional engineering analysis of stress concentrations at notches. (d) A gradual change in cross section compared with a square notch decreases the actual shear 3.4.3.3 When connections in bending members are fastened with split ring connectors, shear plate connectors, bolts, or lag screws (including beams supported by such fasteners or other cases as shown in Figures 3E and 3I) the shear force, V, shall be determined by principles of engineering mechanics (except those given in 3.4.3.1). (a) Where the connection is less than five times the depth, 5d, of the member from its end, the adjusted design shear, V r ', shall be calculated as follows: 2 de Vr Fvbde 3 d 2 (3.4-6)

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 19 where: for split ring or shear plate connections: de = depth of member, less the distance from the unloaded edge of the member to the nearest edge of the nearest split ring or shear plate connector (see Figure 3E), in. for bolt or lag screw connections: Figure 3E de = depth of member, less the distance from the unloaded edge of the member to the center of the nearest bolt or lag screw (see Figure 3E), in. Effective Depth, de, of Members at Connections (b) Where the connection is at least five times the depth, 5d, of the member from its end, the adjusted design shear, V r ', shall be calculated as follows: 2 V r Fvbde (3.4-7) 3 (c) Where concealed hangers are used, the adjusted design shear, V r ', shall be calculated based on the provisions in 3.4.3.2 for notched bending members. 3 DESIGN PROVISIONS AND EQUATIONS 3.5 Bending Members Deflection 3.5.1 Deflection Calculations If deflection is a factor in design, it shall be calculated by standard methods of engineering mechanics considering bending deflections and, when applicable, shear deflections. Consideration for shear deflection is required when the reference modulus of elasticity has not been adjusted to include the effects of shear deflection (see Appendix F). 3.5.2 Long-Term Loading Where total deflection under long-term loading must be limited, increasing member size is one way to provide extra stiffness to allow for this time dependent deformation (see Appendix F). Total deflection, T, shall be calculated as follows: where: T = Kcr LT + ST (3.5-1) Kcr = time dependent deformation (creep) factor = 1.5 for seasoned lumber, structural glued laminated timber, prefabricated wood I-joists, or structural composite lumber used in dry service conditions as defined in 4.1.4, 5.1.4, 7.1.4, and 8.1.4, respectively.

20 DESIGN PROVISIONS AND EQUATIONS = 2.0 for structural glued laminated timber used in wet service conditions as defined in 5.1.4. = 2.0 for wood structural panels used in dry service conditions as defined in 9.1.4. = 2.0 for unseasoned lumber or for seasoned lumber used in wet service conditions as defined in 4.1.4. = 2.0 for cross-laminated timber used in dry service conditions as defined in 10.1.5. LT = immediate deflection due to the long-term component of the design load, in. ST = deflection due to the short-term or normal component of the design load, in. 3.6 Compression Members General 3.6.1 Terminology For purposes of this Specification, the term column refers to all types of compression members, including members forming part of trusses or other structural components. compression design value parallel to grain multiplied by all applicable adjustment factors except the column stability factor, C P. Figure 3F Simple Solid Column 3.6.2 Column Classifications 3.6.2.1 Simple Solid Wood Columns. Simple columns consist of a single piece or of pieces properly glued together to form a single member (see Figure 3F). 3.6.2.2 Spaced Columns, Connector Joined. Spaced columns are formed of two or more individual members with their longitudinal axes parallel, separated at the ends and middle points of their length by blocking and joined at the ends by split ring or shear plate connectors capable of developing the required shear resistance (see 15.2). 3.6.2.3 Built-Up Columns. Individual laminations of mechanically laminated built-up columns shall be designed in accordance with 3.6.3 and 3.7, except that nailed or bolted built-up columns shall be designed in accordance with 15.3. 3.6.3 Strength in Compression Parallel to Grain The actual compression stress or force parallel to grain shall not exceed the adjusted compression design value. Calculations of f c shall be based on the net section area (see 3.1.2) where the reduced section occurs in the critical part of the column length that is most subject to potential buckling. Where the reduced section does not occur in the critical part of the column length that is most subject to potential buckling, calculations of f c shall be based on gross section area. In addition, f c based on net section area shall not exceed the reference 3.6.4 Compression Members Bearing End to End For end grain bearing of wood on wood, and on metal plates or strips see 3.10. 3.6.5 Eccentric Loading or Combined Stresses For compression members subject to eccentric loading or combined flexure and axial loading, see 3.9 and 15.4.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 21 3.6.6 Column Bracing Column bracing shall be installed where necessary to resist wind or other lateral forces (see Appendix A). 3.6.7 Lateral Support of Arches, Studs, and Compression Chords of Trusses Guidelines for providing lateral support and determining e/d in arches, studs, and compression chords of trusses are specified in Appendix A.11. 3.7 Solid Columns 3.7.1 Column Stability Factor, CP 3.7.1.1 When a compression member is supported throughout its length to prevent lateral displacement in all directions, C P = 1.0. 3.7.1.2 The effective column length, e, for a solid column shall be determined in accordance with principles of engineering mechanics. One method for determining effective column length, when end-fixity conditions are known, is to multiply actual column length by the appropriate effective length factor specified in Appendix G, e = (K e )( ). 3.7.1.3 For solid columns with rectangular cross section, the slenderness ratio, e /d, shall be taken as the larger of the ratios e1/d 1 or e2 /d 2 (see Figure 3F) where each ratio has been adjusted by the appropriate buckling length coefficient, K e, from Appendix G. 3.7.1.4 The slenderness ratio for solid columns, e/d, shall not exceed 50, except that during construction e /d shall not exceed 75. 3.7.1.5 The column stability factor shall be calculated as follows: C P 2 * * * ce c ce c ce c 1 F F 1 F F F F 2c 2c c where: (3.7-1) Fc * = reference compression design value parallel to grain multiplied by all applicable adjustment factors except CP (see 2.3), psi 0.822 E min FcE 2 e /d c = 0.8 for sawn lumber c = 0.85 for round timber poles and piles c = 0.9 for structural glued laminated timber, structural composite lumber, and crosslaminated timber 3.7.1.6 For especially severe service conditions and/or extraordinary hazard, use of lower adjusted design values may be necessary. See Appendix H for background information concerning column stability calculations and Appendix F for information concerning coefficient of variation in modulus of elasticity (COV E ). 3.7.2 Tapered Columns For design of a column with rectangular cross section, tapered at one or both ends, the representative dimension, d, for each face of the column shall be derived as follows: d min d d min (dmax d min) a 0.151 (3.7-2) d max where: d = representative dimension for tapered column, in. dmin = the minimum dimension for that face of the column, in. dmax = the maximum dimension for that face of the column, in. Support Conditions Large end fixed, small end unsupported a = 0.70 or simply supported Small end fixed, large end unsupported a = 0.30 or simply supported Both ends simply supported: Tapered toward one end a = 0.50 Tapered toward both ends a = 0.70 For all other support conditions: d d min (dmax d min)(1 / 3) (3.7-3) 3 DESIGN PROVISIONS AND EQUATIONS

22 DESIGN PROVISIONS AND EQUATIONS Calculations of f c and C P shall be based on the representative dimension, d. In addition, f c at any cross section in the tapered column shall not exceed the reference compression design value parallel to grain multiplied by all applicable adjustment factors except the column stability factor, C P. 3.7.3 Round Columns The design of a column of round cross section shall be based on the design calculations for a square column of the same cross-sectional area and having the same degree of taper. Reference design values and special design provisions for round timber poles and piles are provided in Chapter 6. 3.8 Tension Members 3.8.1 Tension Parallel to Grain The actual tension stress or force parallel to grain shall be based on the net section area (see 3.1.2) and shall not exceed the adjusted tension design value. 3.8.2 Tension Perpendicular to Grain Designs that induce tension stress perpendicular to grain shall be avoided whenever possible (see References 16 and 19). When tension stress perpendicular to grain cannot be avoided, mechanical reinforcement sufficient to resist all such stresses shall be considered (see References 52 and 53 for additional information). 3.9 Combined Bending and Axial Loading 3.9.1 Bending and Axial Tension Members subjected to a combination of bending and axial tension (see Figure 3G) shall be so proportioned that: and ft f F F t b * b 1.0 fb ft ** 1.0 F b where: (3.9-1) (3.9-2) Fb * = reference bending design value multiplied by all applicable adjustment factors except CL, psi Fb ** = reference bending design value multiplied by all applicable adjustment factors except CV, psi Figure 3G Combined Bending and Axial Tension 3.9.2 Bending and Axial Compression Members subjected to a combination of bending about one or both principal axes and axial compression (see Figure 3H) shall be so proportioned that: 2 f c f b1 F c Fb1 1 fc FcE1 fb2 F 1 f F f F b2 c ce2 b1 be 2 1.0 (3.9-3)

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 23 and f F c ce2 where: and and f f f F F b1 be 2 1.0 0.822 E min ( /d ) c ce1 2 e1 1 f F F 0.822 E min ( /d ) c ce2 2 e2 2 1.20 E (R ) min b1 be 2 B (3.9-4) for either uniaxial edgewise bending or biaxial bending for uniaxial flatwise bending or biaxial bending for biaxial bending fb1 = actual edgewise bending stress (bending load applied to narrow face of member), psi fb2 = actual flatwise bending stress (bending load applied to wide face of member), psi d1 = wide face dimension (see Figure 3H), in. Effective column lengths, e1 and e2, shall be determined in accordance with 3.7.1.2. F c ', F ce1, and F ce2 shall be determined in accordance with 2.3 and 3.7. F b1 ', F b2 ', and F be shall be determined in accordance with 2.3 and 3.3.3. 3.9.3 Eccentric Compression Loading See 15.4 for members subjected to combined bending and axial compression due to eccentric loading, or eccentric loading in combination with other loads. Figure 3H Combined Bending and Axial Compression 3 DESIGN PROVISIONS AND EQUATIONS d2 = narrow face dimension (see Figure 3H), in. 3.10 Design for Bearing 3.10.1 Bearing Parallel to Grain 3.10.1.1 The actual compressive bearing stress parallel to grain shall be based on the net bearing area and shall not exceed the reference compression design value parallel to grain multiplied by all applicable adjustment factors except the column stability factor, C P. 3.10.1.2 F c *, the reference compression design values parallel to grain multiplied by all applicable adjustment factors except the column stability factor, applies to end-to-end bearing of compression members provided there is adequate lateral support and the end cuts are accurately squared and parallel. 3.10.1.3 When f c > (0.75)(F c * ) bearing shall be on a metal plate or strap, or on other equivalently durable, rigid, homogeneous material with sufficient stiffness to distribute the applied load. Where a rigid insert is required for end-to-end bearing of compression members, it shall be equivalent to 20-gage metal plate or better, inserted with a snug fit between abutting ends. 3.10.2 Bearing Perpendicular to Grain The actual compression stress perpendicular to grain shall be based on the net bearing area and shall not exceed the adjusted compression design value perpendicular to grain, f c F c '. When calculating bearing area at the ends of bending members, no allowance shall be made for the fact that as the member bends, pressure upon the inner edge of the bearing is greater than at the member end.

24 DESIGN PROVISIONS AND EQUATIONS 3.10.3 Bearing at an Angle to Grain The adjusted bearing design value at an angle to grain (see Figure 3I and Appendix J) shall be calculated as follows: F F F F sin F cos where: * c c * 2 2 c c (3.10-1) = angle between direction of load and direction of grain (longitudinal axis of member), degrees Equation 3.10-2 gives the following bearing area factors, C b, for the indicated bearing length on such small areas as plates and washers: Table 3.10.4 Bearing Area Factors, Cb b 0.5" 1" 1.5" 2" 3" 4" 6" or more C b 1.75 1.38 1.25 1.19 1.13 1.10 1.00 For round bearing areas such as washers, the bearing length, b, shall be equal to the diameter. Figure 3 Bearing at an Angle to Grain 3.10.4 Bearing Area Factor, Cb Reference compression design values perpendicular to grain, F c, apply to bearings of any length at the ends of a member, and to all bearings 6" or more in length at any other location. For bearings less than 6" in length and not nearer than 3" to the end of a member, the reference compression design value perpendicular to grain, F c, shall be permitted to be multiplied by the following bearing area factor, C b : 0.375 C b (3.10-2) b where: b b = bearing length measured parallel to grain, in.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 25 SAWN LUMBER 4 4.1 General 26 4.2 Reference Design Values 27 4.3 Adjustment of Reference Design Values 28 4.4 Special Design Considerations 31 Table 4.3.1 Applicability of Adjustment Factors for Sawn Lumber... 29 Table 4.3.8 Incising Factors, C i... 30

26 SAWN LUMBER 4.1 General 4.1.1 Scope Chapter 4 applies to engineering design with sawn lumber. Design procedures, reference design values, and other information herein apply only to lumber complying with the requirements specified below. 4.1.2 Identification of Lumber 4.1.2.1 When the reference design values specified herein are used, the lumber, including end-jointed or edge-glued lumber, shall be identified by the grade mark of, or certificate of inspection issued by, a lumber grading or inspection bureau or agency recognized as being competent (see Reference 31). A distinct grade mark of a recognized lumber grading or inspection bureau or agency, indicating that joint integrity is subject to qualification and quality control, shall be applied to glued lumber products. 4.1.2.2 Lumber shall be specified by commercial species and grade names, or by required levels of design values as listed in Tables 4A, 4B, 4C, 4D, 4E, and 4F (published in the Supplement to this Specification). 4.1.3 Definitions 4.1.3.1 Structural sawn lumber consists of lumber classifications known as Dimension, Beams and Stringers, Posts and Timbers, and Decking, with design values assigned to each grade. 4.1.3.2 Dimension refers to lumber from 2" to 4" (nominal) thick, and 2" (nominal) or more in width. Dimension lumber is further classified as Structural Light Framing, Light Framing, Studs, and Joists and Planks (see References 42, 43, 44, 45, 46, 47, and 49 for additional information). 4.1.3.3 Beams and Stringers refers to lumber of rectangular cross section, 5" (nominal) or more thick, with width more than 2" greater than thickness, graded with respect to its strength in bending when loaded on the narrow face. 4.1.3.4 Posts and Timbers refers to lumber of square or approximately square cross section, 5" x 5" (nominal) and larger, with width not more than 2" greater than thickness, graded primarily for use as posts or columns carrying longitudinal load. 4.1.3.5 Decking refers to lumber from 2" to 4" (nominal) thick, tongued and grooved, or grooved for spline on the narrow face, and intended for use as a roof, floor, or wall membrane. Decking is graded for application in the flatwise direction, with the wide face of the decking in contact with the supporting members, as normally installed. 4.1.4 Moisture Service Condition of Lumber The reference design values for lumber specified herein are applicable to lumber that will be used under dry service conditions such as in most covered structures, where the moisture content in use will be a maximum of 19%, regardless of the moisture content at the time of manufacture. For lumber used under conditions where the moisture content of the wood in service will exceed 19% for an extended period of time, the design values shall be multiplied by the wet service factors, C M, specified in Tables 4A, 4B, 4C, 4D, 4E, and 4F. 4.1.5 Lumber Sizes 4.1.5.1 Lumber sizes referred to in this Specification are nominal sizes. Computations to determine the required sizes of members shall be based on the net dimensions (actual sizes) and not the nominal sizes. The dressed sizes specified in Reference 31 shall be accepted as the minimum net sizes associated with nominal dimensions (see Table 1A in the Supplement to this Specification). 4.1.5.2 For 4" (nominal) or thinner lumber, the net DRY dressed sizes shall be used in all computations of structural capacity regardless of the moisture content at the time of manufacture or use. 4.1.5.3 For 5" (nominal) and thicker lumber, the net GREEN dressed sizes shall be used in computations of structural capacity regardless of the moisture content at the time of manufacture or use. 4.1.5.4 Where a design is based on rough sizes or special sizes, the applicable moisture content and size used in design shall be clearly indicated in plans or specifications. 4.1.6 End-Jointed or Edge-Glued Lumber Reference design values for sawn lumber are applicable to structural end-jointed or edge-glued lumber of the same species and grade. Such use shall include, but not be limited to light framing, studs, joists, planks, and decking. When finger jointed lumber is marked STUD USE ONLY or VERTICAL USE ONLY such lumber shall be limited to use where any bending or tension stresses are of short duration.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 27 4.1.7 Resawn or Remanufactured Lumber 4.1.7.1 When structural lumber is resawn or remanufactured, it shall be regraded, and reference design values for the regraded material shall apply (see References 16, 42, 43, 44, 45, 46, 47, and 49). 4.1.7.2 When sawn lumber is cross cut to shorter lengths, the requirements of 4.1.7.1 shall not apply, except for reference bending design values for those Beam and Stringer grades where grading provisions for the middle 1/3 of the length of the piece differ from grading provisions for the outer thirds. 4.2 Reference Design Values 4.2.1 Reference Design Values 4.2.4 Modulus of Elasticity, E 4 Reference design values for visually graded lumber and for mechanically graded dimension lumber are specified in Tables 4A, 4B, 4C, 4D, 4E, and 4F (published in the Supplement to this Specification). The reference design values in Tables 4A, 4B, 4C, 4D, 4E, and 4F are taken from the published grading rules of the agencies cited in References 42, 43, 44, 45, 46, 47, and 49. 4.2.2 Other Species and Grades Reference design values for species and grades of lumber not otherwise provided herein shall be established in accordance with appropriate ASTM standards and other technically sound criteria (see References 16, 18, 19, and 31). 4.2.3 Basis for Reference Design Values 4.2.3.1 The reference design values in Tables 4A, 4B, 4C, 4D, 4E, and 4F are for the design of structures where an individual member, such as a beam, girder, post or other member, carries or is responsible for carrying its full design load. For repetitive member uses see 4.3.9. 4.2.3.2 Visually Graded Lumber. Reference design values for visually graded lumber in Tables 4A, 4B, 4C, 4D, 4E, and 4F are based on the provisions of ASTM Standards D 245 and D 1990. 4.2.3.3 Machine Stress Rated (MSR) Lumber and Machine Evaluated Lumber (MEL). Reference design values for machine stress rated lumber and machine evaluated lumber in Table 4C are determined by visual grading and nondestructive pretesting of individual pieces. 4.2.4.1 Average Values. Reference design values for modulus of elasticity assigned to the visually graded species and grades of lumber listed in Tables 4A, 4B, 4C, 4D, 4E, and 4F are average values which conform to ASTM Standards D 245 and D 1990. Adjustments in modulus of elasticity have been taken to reflect increases for seasoning, increases for density where applicable, and, where required, reductions have been made to account for the effect of grade upon stiffness. Reference modulus of elasticity design values are based upon the species or species group average in accordance with ASTM Standards D 1990 and D 2555. 4.2.4.2 Special Uses. Average reference modulus of elasticity design values listed in Tables 4A, 4B, 4C, 4D, 4E, and 4F are to be used in design of repetitive member systems and in calculating the immediate deflection of single members which carry their full design load. In special applications where deflection is a critical factor, or where amount of deformation under long-term loading must be limited, the need for use of a reduced modulus of elasticity design value shall be determined. See Appendix F for provisions on design value adjustments for special end use requirements. 4.2.5 Bending, Fb 4.2.5.1 Dimension Grades. Adjusted bending design values for Dimension grades apply to members with the load applied to either the narrow or wide face. 4.2.5.2 Decking Grades. Adjusted bending design values for Decking grades apply only when the load is applied to the wide face. 4.2.5.3 Post and Timber Grades. Adjusted bending design values for Post and Timber grades apply to members with the load applied to either the narrow or wide face. 4.2.5.4 Beam and Stringer Grades. Adjusted bending design values for Beam and Stringer grades apply to members with the load applied to the narrow face. SAWN LUMBER

28 SAWN LUMBER When Post and Timber sizes of lumber are graded to Beam and Stringer grade requirements, design values for the applicable Beam and Stringer grades shall be used. Such lumber shall be identified in accordance with 4.1.2.1 as conforming to Beam and Stringer grades. 4.2.5.5 Continuous or Cantilevered Beams. When Beams and Stringers are used as continuous or cantilevered beams, the design shall include a requirement that the grading provisions applicable to the middle 1/3 of the length (see References 42, 43, 44, 45, 46, 47, and 49) shall be applied to at least the middle 2/3 of the length of pieces to be used as two span continuous beams, and to the entire length of pieces to be used over three or more spans or as cantilevered beams. 4.2.6 Compression Perpendicular to Grain, Fc For sawn lumber, the reference compression design values perpendicular to grain are based on a deformation limit that has been shown by experience to provide for adequate service in typical wood frame construction. The reference compression design values perpendicular to grain specified in Tables 4A, 4B, 4C, 4D, 4E, and 4F are species group average values associated with a deformation level of 0.04" for a steel plate on wood member loading condition. One method for limiting deformation in special applications where it is critical, is use of a reduced compression design value perpendicular to grain. The following equation shall be used to calculate the compression design value perpendicular to grain for a reduced deformation level of 0.02": where: Fc 0.02 = 0.73 Fc (4.2-1) Fc 0.02 = compression perpendicular to grain design value at 0.02" deformation limit, psi Fc = reference compression perpendicular to grain design value at 0.04" deformation limit (as published in Tables 4A, 4B, 4C, 4D, 4E, and 4F), psi 4.3 Adjustment of Reference Design Values 4.3.1 General Reference design values (F b, F t, F v, F c, F c, E, E min ) from Tables 4A, 4B, 4C, 4D, 4E, and 4F shall be multiplied by the adjustment factors specified in Table 4.3.1 to determine adjusted design values (F b ', F t ', F v ', F c', F c ', E', E min '). 4.3.2 Load Duration Factor, CD (ASD Only) All reference design values except modulus of elasticity, E, modulus of elasticity for beam and column stability, E min, and compression perpendicular to grain, F c, shall be multiplied by load duration factors, C D, as specified in 2.3.2. 4.3.3 Wet Service Factor, CM Reference design values for structural sawn lumber are based on the moisture service conditions specified in 4.1.4. When the moisture content of structural members in use differs from these moisture service conditions, reference design values shall be multiplied by the wet service factors, C M, specified in Tables 4A, 4B, 4C, 4D, 4E, and 4F. 4.3.4 Temperature Factor, Ct When structural members will experience sustained exposure to elevated temperatures up to 150F (see Appendix C), reference design values shall be multiplied by the temperature factors, C t, specified in 2.3.3.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 29 Table 4.3.1 Applicability of Adjustment Factors for Sawn Lumber ASD only ASD and LRFD LRFD only Load Duration Factor Wet Service Factor Temperature Factor Beam Stability Factor Size Factor Flat Use Factor Incising Factor Repetitive Member Factor Column Stability Factor Buckling Stiffness Factor Bearing Area Factor Format Conversion Factor K F Resistance Factor Time Effect Factor 4 F b ' = F b x C D C M C t C L C F C fu C i C r - - - 2.54 0.85 F t ' = F t x C D C M C t - C F - C i - - - - 2.70 0.80 F v ' = F v x C D C M C t - - - C i - - - - 2.88 0.75 SAWN LUMBER ' F c = F c x C D C M C t - C F - C i - C P - - 2.40 0.90 ' F c = F c x - C M C t - - - C i - - - C b 1.67 0.90 - E ' = E x - C M C t - - - C i - - - - - - - ' E min = E min x - C M C t - - - C i - - C T - 1.76 0.85-4.3.5 Beam Stability Factor, CL Reference bending design values, F b, shall be multiplied by the beam stability factor, C L, specified in 3.3.3. 4.3.6 Size Factor, CF 4.3.6.1 Reference bending, tension, and compression parallel to grain design values for visually graded dimension lumber 2" to 4" thick shall be multiplied by the size factors specified in Tables 4A and 4B. 4.3.6.2 Where the depth of a rectangular sawn lumber bending member 5" or thicker exceeds 12", the reference bending design values, F b, in Table 4D shall be multiplied by the following size factor: 4.3.6.3 For beams of circular cross section with a diameter greater than 13.5", or for 12" or larger square beams loaded in the plane of the diagonal, the size factor shall be determined in accordance with 4.3.6.2 on the basis of an equivalent conventionally loaded square beam of the same cross-sectional area. 4.3.6.4 Reference bending design values for all species of 2" thick or 3" thick Decking, except Redwood, shall be multiplied by the size factors specified in Table 4E. 4.3.7 Flat Use Factor, Cfu When sawn lumber 2" to 4" thick is loaded on the wide face, multiplying the reference bending design value, F b, by the flat use factors, C fu, specified in Tables 4A, 4B, 4C, and 4F, shall be permitted. 4.3.8 Incising Factor, Ci 19 C (12 / d) 1.0 (4.3-1) F Reference design values shall be multiplied by the following incising factor, C i, when dimension lumber is incised parallel to grain a maximum depth of 0.4", a maximum length of 3/8", and density of incisions up to

30 SAWN LUMBER 1100/ft 2. Incising factors shall be determined by test or by calculation using reduced section properties for incising patterns exceeding these limits. Table 4.3.8 Incising Factors, Ci Design Value C i E, E min 0.95 F b, F t, F c, F v 0.80 F c 1.00 4.3.9 Repetitive Member Factor, Cr Reference bending design values, F b, in Tables 4A, 4B, 4C, and 4F for dimension lumber 2" to 4" thick shall be multiplied by the repetitive member factor, C r = 1.15, where such members are used as joists, truss chords, rafters, studs, planks, decking, or similar members which are in contact or spaced not more than 24" on center, are not less than three in number and are joined by floor, roof or other load distributing elements adequate to support the design load. (A load distributing element is any adequate system that is designed or has been proven by experience to transmit the design load to adjacent members, spaced as described above, without displaying structural weakness or unacceptable deflection. Subflooring, flooring, sheathing, or other covering elements and nail gluing or tongue-andgroove joints, and through nailing generally meet these criteria.) Reference bending design values in Table 4E for visually graded Decking have already been multiplied by C r = 1.15. 4.3.10 Column Stability Factor, CP Reference compression design values parallel to grain, F c, shall be multiplied by the column stability factor, C P, specified in 3.7. 4.3.11 Buckling Stiffness Factor, CT Reference modulus of elasticity for beam and column stability, E min, shall be permitted to be multiplied by the buckling stiffness factor, C T, as specified in 4.4.2. 4.3.12 Bearing Area Factor, Cb Reference compression design values perpendicular to grain, F c, shall be permitted to be multiplied by the bearing area factor, C b, as specified in 3.10.4. 4.3.13 Pressure-Preservative Treatment Reference design values apply to sawn lumber pressure-treated by an approved process and preservative (see Reference 30). Load duration factors greater than 1.6 shall not apply to structural members pressuretreated with water-borne preservatives. 4.3.14 Format Conversion Factor, KF (LRFD Only) For LRFD, reference design values shall be multiplied by the format conversion factor, K F, specified in Table 4.3.1. 4.3.15 Resistance Factor, (LRFD Only) For LRFD, reference design values shall be multiplied by the resistance factor,, specified in Table 4.3.1. 4.3.16 Time Effect Factor, (LRFD Only) For LRFD, reference design values shall be multiplied by the time effect factor, λ, specified in Appendix N.3.3.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 31 4.4 Special Design Considerations 4.4.1 Stability of Bending Members 4.4.2 Wood Trusses 4.4.1.1 Sawn lumber bending members shall be designed in accordance with the lateral stability calculations in 3.3.3 or shall meet the lateral support requirements in 4.4.1.2 and 4.4.1.3. 4.4.1.2 As an alternative to 4.4.1.1, rectangular sawn lumber beams, rafters, joists, or other bending members, shall be designed in accordance with the following provisions to provide restraint against rotation or lateral displacement. If the depth to breadth, d/b, based on nominal dimensions is: (a) d/b 2; no lateral support shall be required. (b) 2 < d/b 4; the ends shall be held in position, as by full depth solid blocking, bridging, hangers, nailing, or bolting to other framing members, or other acceptable means. (c) 4 < d/b 5; the compression edge of the member shall be held in line for its entire length to prevent lateral displacement, as by adequate sheathing or subflooring, and ends at point of bearing shall be held in position to prevent rotation and/or lateral displacement. (d) 5 < d/b 6; bridging, full depth solid blocking or diagonal cross bracing shall be installed at intervals not exceeding 8 feet, the compression edge of the member shall be held in line as by adequate sheathing or subflooring, and the ends at points of bearing shall be held in position to prevent rotation and/or lateral displacement. (e) 6 < d/b 7; both edges of the member shall be held in line for their entire length and ends at points of bearing shall be held in position to prevent rotation and/or lateral displacement. 4.4.1.3 If a bending member is subjected to both flexure and axial compression, the depth to breadth ratio shall be no more than 5 to 1 if one edge is firmly held in line. If under all combinations of load, the unbraced edge of the member is in tension, the depth to breadth ratio shall be no more than 6 to 1. 4.4.2.1 Increased chord stiffness relative to axial loads where a 2" x 4" or smaller sawn lumber truss compression chord is subjected to combined flexure and axial compression under dry service condition and has 3/8" or thicker plywood sheathing nailed to the narrow face of the chord in accordance with code required roof sheathing fastener schedules (see References 32, 33, and 34), shall be permitted to be accounted for by multiplying the reference modulus of elasticity design value for beam and column stability, E min, by the buckling stiffness factor, C T, in column stability calculations (see 3.7 and Appendix H). When e < 96", C T shall be calculated as follows: where: K C M e T 1 KE T (4.4-1) e = effective column length of truss compression chord (see 3.7), in. KM = 2300 for wood seasoned to 19% moisture content or less at the time of plywood attachment. = 1200 for unseasoned or partially seasoned wood at the time of plywood attachment. KT = 1 1.645(COVE) = 0.59 for visually graded lumber = 0.75 for machine evaluated lumber (MEL) = 0.82 for products with COVE 0.11 (see Appendix F.2) When e > 96", C T shall be calculated based on e = 96". 4.4.2.2 For additional information concerning metal plate connected wood trusses see Reference 9. 4 SAWN LUMBER

32 SAWN LUMBER 4.4.3 Notches 4.4.3.1 End notches, located at the ends of sawn lumber bending members for bearing over a support, shall be permitted, and shall not exceed 1/4 the beam depth (see Figure 4A). 4.4.3.2 Interior notches, located in the outer thirds of the span of a single span sawn lumber bending member, shall be permitted, and shall not exceed 1/6 the depth of the member. Interior notches on the tension side of 3-½" or greater thickness (4" nominal thickness) sawn lumber bending members are not permitted (see Figure 4A). 4.4.3.3 See 3.1.2 and 3.4.3 for effect of notches on strength. Figure 4A Notch Limitations for Sawn Lumber Beams

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 33 STRUCTURAL GLUED LAMINATED TIMBER 5 5.1 General 34 5.2 Reference Design Values 35 5.3 Adjustment of Reference Design Values 36 5.4 Special Design Considerations 39 Table 5.1.3 Table 5.2.8 Table 5.3.1 Net Finished Widths of Structural Glued Laminated Timbers... 34 Radial Tension Design Factors, F rt, for Curved Members... 36 Applicability of Adjustment Factors for Structural Glued Laminated Timber... 37

34 STRUCTURAL GLUED LAMINATED TIMBER 5.1 General 5.1.1 Scope 5.1.1.1 Chapter 5 applies to engineering design with structural glued laminated timber. Basic requirements are provided in this Specification; for additional detail, see Reference 52. 5.1.1.2 Design procedures, reference design values and other information provided herein apply only to structural glued laminated timber conforming to all pertinent provisions of the specifications referenced in the footnotes to Tables 5A, 5B, 5C, and 5D and produced in accordance with ANSI A190.1. 5.1.2 Definition The term structural glued laminated timber refers to an engineered, stress rated product of a timber laminating plant, comprising assemblies of specially selected and prepared wood laminations bonded together with adhesives. The grain of all laminations is approximately parallel longitudinally. The separate laminations shall not exceed 2" in net thickness and are permitted to be comprised of: one piece pieces joined end-to-end to form any length pieces placed or glued edge-to-edge to make wider ones pieces bent to curved form during gluing. Table 5.1.3 Nominal Width of Laminations (in.) Net Finished Width (in.) Net Finished Widths of Structural Glued Laminated Timbers 3 4 6 8 10 12 14 16 Western Species 2-½ 3-1/8 5-1/8 6-¾ 8-¾ 10-¾ 12-¼ 14-¼ Southern Pine 2-½ 3-1/8 5-1/8 6-¾ 8-½ 10-½ 12-½ 14-½ 5.1.4 Service Conditions 5.1.4.1 Reference design values for dry service conditions shall apply when the moisture content in service is less than 16%, as in most covered structures. 5.1.4.2 Reference design values for glued laminated timber shall be multiplied by the wet service factors, C M, specified in Tables 5A, 5B, 5C, and 5D when the moisture content in service is 16% or greater, as may occur in exterior or submerged construction, or humid environments. 5.1.3 Standard Sizes 5.1.3.1 Normal standard finished widths of structural glued laminated members shall be as shown in Table 5.1.3. This Specification is not intended to prohibit other finished widths where required to meet the size requirements of a design or to meet other special requirements. 5.1.3.2 The length and net dimensions of all members shall be specified. Additional dimensions necessary to define non-prismatic members shall be specified.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 35 5.2 Reference Design Values 5.2.1 Reference Design Values 5.2.4 Bending, Fbx +, Fbx -, Fby Reference design values for softwood and hardwood structural glued laminated timber are specified in Tables 5A, 5B, 5C, and 5D (published in a separate Supplement to this Specification). The reference design values in Tables 5A, 5B, 5C, and 5D are a compilation of the reference design values provided in the specifications referenced in the footnotes to the tables. 5.2.2 Orientation of Member Reference design values for structural glued laminated timber are dependent on the orientation of the laminations relative to the applied loads. Subscripts are used to indicate design values corresponding to a given orientation. The orientations of the crosssectional axes for structural glued laminated timber are shown in Figure 5A. The x-x axis runs parallel to the wide face of the laminations. The y-y axis runs perpendicular to the wide faces of the laminations. Figure 5A Axis Orientations The reference bending design values, F bx + and F bx, shall apply to members with loads causing bending about the x-x axis. The reference bending design value for positive bending, F bx +, shall apply for bending stresses causing tension at the bottom of the beam. The reference bending design value for negative bending, F bx -, shall apply for bending stresses causing tension at the top of the beam. The reference bending design value, F by, shall apply to members with loads causing bending about the y-y axis. 5.2.5 Compression Perpendicular to Grain, Fcx, Fcy The reference compression design value perpendicular to grain, F cx, shall apply to members with bearing loads on the wide faces of the laminations. The reference compression design value perpendicular to grain, F cy, shall apply to members with bearing loads on the narrow edges of the laminations. The reference compression design values perpendicular to grain are based on a deformation limit of 0.04" obtained from testing in accordance with ASTM D143. The compression perpendicular to grain stress associated with a 0.02" deformation limit shall be permitted to be calculated as 73% of the reference value (See also 4.2.6). 5.2.6 Shear Parallel to Grain, Fvx, Fvy 5 STRUCTURAL GLUED LAMINATED TIMBER 5.2.3 Balanced and Unbalanced Layups Structural glued laminated timbers are permitted to be assembled with laminations of the same lumber grades placed symmetrically or asymmetrically about the neutral axis of the member. Symmetrical layups are referred to as balanced and have the same design values for positive and negative bending. Asymmetrical layups are referred to as unbalanced and have lower design values for negative bending than for positive bending. The top side of unbalanced members is required to be marked TOP by the manufacturer. The reference shear design value parallel to grain, F vx shall apply to members with shear loads causing bending about the x-x axis. The reference shear design value parallel to grain, F vy, shall apply to members with shear loads causing bending about the y-y axis. The reference shear design values parallel to grain shall apply to prismatic members except those subject to impact or repetitive cyclic loads. For non-prismatic members and for all members subject to impact or repetitive cyclic loads, the reference shear design values parallel to grain shall be multiplied by the shear reduction factor specified in 5.3.10. This reduction shall also apply to the design of connections transferring loads through mechanical fasteners (see 3.4.3.3, 11.1.2 and 11.2.2).

36 STRUCTURAL GLUED LAMINATED TIMBER Prismatic members shall be defined as straight or cambered members with constant cross-section. Nonprismatic members include, but are not limited to: arches, tapered beams, curved beams, and notched members. The reference shear design value parallel to grain, F vy, is tabulated for members with four or more laminations. For members with two or three laminations, the reference design value shall be multiplied by 0.84 or 0.95, respectively. 5.2.7 Modulus of Elasticity, Ex, Ex min, Ey, Ey min The reference modulus of elasticity, E x, shall be used for determination of deflections due to bending about the x-x axis. The reference modulus of elasticity, E x min, shall be used for beam and column stability calculations for members buckling about the x-x axis. The reference modulus of elasticity, E y, shall be used for determination of deflections due to bending about the y-y axis. The reference modulus of elasticity, E y min, shall be used for beam and column stability calculations for members buckling about the y-y axis. For the calculation of extensional deformations, the axial modulus of elasticity shall be permitted to be estimated as E axial = 1.05E y. 5.2.8 Radial Tension, Frt For curved bending members, the following reference radial tension design values perpendicular to grain, F rt, shall apply: Table 5.2.8 Southern Pine Douglas Fir-Larch, Douglas Fir South, Hem-Fir, Western Woods, and Canadian softwood species Radial Tension Design Values, Frt, for Curved Members all loading conditions wind or earthquake loading other types of loading 5.2.9 Radial Compression, Frc F rt = (1/3)F vx C vr F rt = (1/3)F vx C vr F rt = 15 psi For curved bending members, the reference radial compression design value, F rc, shall be taken as the reference compression perpendicular to grain design value on the side face, F cy. 5.2.10 Other Species and Grades Reference design values for species and grades of structural glued laminated timber not otherwise provided herein shall be established in accordance with Reference 22, or shall be based on other substantiated information from an approved source. 5.3 Adjustment of Reference Design Values 5.3.1 General Reference design values (F b, F t, F v, F c, F c, F rt, E, E min ) provided in 5.2 and Tables 5A, 5B, 5C, and 5D shall be multiplied by the adjustment factors specified in Table 5.3.1 to determine adjusted design values (F b ', F t ', F v ', F c ', F c ', F rt ', E', E min '). 5.3.2 Load Duration Factor, CD (ASD only) 5.3.3 Wet Service Factor, CM Reference design values for structural glued laminated timber are based on the moisture service conditions specified in 5.1.4. When the moisture content of structural members in use differs from these moisture service conditions, reference design values shall be multiplied by the wet service factors, C M, specified in Tables 5A, 5B, 5C, and 5D. All reference design values except modulus of elasticity, E, modulus of elasticity for beam and column stability, E min, and compression perpendicular to grain, F c, shall be multiplied by load duration factors, C D, as specified in 2.3.2.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 37 Table 5.3.1 Applicability of Adjustment Factors for Structural Glued Laminated Timber ASD only ASD and LRFD LRFD only Load Duration Factor 5.3.4 Temperature Factor, Ct When structural members will experience sustained exposure to elevated temperatures up to 150F (see Appendix C), reference design values shall be multiplied by the temperature factors, C t, specified in 2.3.3. 5.3.5 Beam Stability Factor, CL Reference bending design values, F b, shall be multiplied by the beam stability factor, C L, specified in 3.3.3. The beam stability factor, C L, shall not apply simultaneously with the volume factor, C V, for structural glued laminated timber bending members (see 5.3.6). Therefore, the lesser of these adjustment factors shall apply. Wet Service Factor Temperature Factor Beam Stability Factor 1 Volume Factor 1 Flat Use Factor F b ' = F b x C D C M C t C L C V C fu C c C I - - - 2.54 0.85 F t ' = F t x C D C M C t - - - - - - - - 2.70 0.80 F v ' = F v x C D C M C t - - - - - C vr - - 2.88 0.75 F rt ' = F rt x C D C M C t - - - - - - - - 2.88 0.75 F c ' = F c x C D C M C t - - - - - - C P - 2.40 0.90 F c ' = F c x - C M C t - - - - - - - C b 1.67 0.90 - E ' = E x - C M C t - - - - - - - - - - - E min ' = E min x - C M C t - - - - - - - - 1.76 0.85-1. The beam stability factor, C L, shall not apply simultaneously with the volume factor, C V, for structural glued laminated timber bending members (see 5.3.6). Therefore, the lesser of these adjustment factors shall apply. 5.3.6 Volume Factor, CV When structural glued laminated timber members are loaded in bending about the x-x axis, the reference bending design values, F bx +, and F bx -, shall be multiplied by the following volume factor: 1/x 1/x 1/x 21 12 5.125 C V = 1.0 L d b Curvature Factor Stress Interaction Factor Shear Reduction Factor Column Stability Factor Bearing Area Factor (5.3-1) where: L = length of bending member between points of zero moment, ft Format Conversion Factor K F Resistance Factor Time Effect Factor d = depth of bending member, in. b = width (breadth) of bending member. For multiple piece width layups, b = width of widest piece used in the layup. Thus, b 10.75". x = 20 for Southern Pine x = 10 for all other species 5 STRUCTURAL GLUED LAMINATED TIMBER

38 STRUCTURAL GLUED LAMINATED TIMBER The volume factor, C V, shall not apply simultaneously with the beam stability factor, C L (see 3.3.3). Therefore, the lesser of these adjustment factors shall apply. 5.3.7 Flat Use Factor, Cfu When structural glued laminated timber is loaded in bending about the y-y axis and the member dimension parallel to the wide face of the laminations, d y (see Figure 5B), is less than 12", the reference bending design value, F by, shall be permitted to be multiplied by the flat use factor, C fu, specified in Tables 5A, 5B, 5C, and 5D, or as calculated by the following formula: 12 C fu = dy Figure 5B 1/9 Depth, dy, for Flat Use Factor (5.3-2) 5.3.9 Stress Interaction Factor, C I For the tapered portion of bending members tapered on the compression face, the reference bending design value, F bx, shall be multiplied by the following stress interaction factor: 1 C I (5.3-4) 1 F tan F C F tan F where: 2 2 2 b v vr b c = angle of taper, degrees For members tapered on the compression face, the stress interaction factor, C I, shall not apply simultaneously with the volume factor, C V, therefore, the lesser of these adjustment factors shall apply. For the tapered portion of bending members tapered on the tension face, the reference bending design value, F bx, shall be multiplied by the following stress interaction factor: 1 C I (5.3-5) 1 F tan F C F tan F where: 2 2 2 b v vr b rt d y (in.) = angle of taper, degrees 5.3.8 Curvature Factor, Cc For curved portions of bending members, the reference bending design value shall be multiplied by the following curvature factor: Cc = 1 (2000)(t / R) 2 (5.3-3) where: t = thickness of laminations, in. R = radius of curvature of inside face of member, in. t/r 1/100 for hardwoods and Southern Pine t/r 1/125 for other softwoods The curvature factor shall not apply to reference design values in the straight portion of a member, regardless of curvature elsewhere. For members tapered on the tension face, the stress interaction factor, C I, shall not apply simultaneously with the beam stability factor, C L, therefore, the lesser of these adjustment factors shall apply. Taper cuts on the tension face of structural glued laminated timber beams are not recommended. 5.3.10 Shear Reduction Factor, Cvr The reference shear design values, F vx and F vy, shall be multiplied by the shear reduction factor, C vr = 0.72 where any of the following conditions apply: 1. Design of non-prismatic members. 2. Design of members subject to impact or repetitive cyclic loading. 3. Design of members at notches (3.4.3.2). 4. Design of members at connections (3.4.3.3, 11.1.2, 11.2.2). 5.3.11 Column Stability Factor, CP Reference compression design values parallel to grain, F c, shall be multiplied by the column stability factor, C P, specified in 3.7.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 39 5.3.12 Bearing Area Factor, Cb Reference compression design values perpendicular to grain, F c, shall be permitted to be multiplied by the bearing area factor, C b, as specified in 3.10.4. 5.3.13 Pressure-Preservative Treatment Reference design values apply to structural glued laminated timber treated by an approved process and preservative (see Reference 30). Load duration factors greater than 1.6 shall not apply to structural members pressure-treated with water-borne preservatives. 5.4 Special Design Considerations 5.4.1 Curved Bending Members with Constant Cross Section 5.4.1.1 Curved bending members with constant rectangular cross section shall be designed for flexural strength in accordance with 3.3. 5.4.1.2 Curved bending members with constant rectangular cross section shall be designed for shear strength in accordance with 3.4, except that the provisions of 3.4.3.1 shall not apply. The shear reduction factor from 5.3.10 shall apply. 5.4.1.3 The radial stress induced by a bending moment in a curved bending member of constant rectangular cross section is: where: 3M fr 2Rbd M = bending moment, in.-lbs R = radius of curvature at center line of member, in. (5.4-1) Where the bending moment is in the direction tending to decrease curvature (increase the radius), the radial stress shall not exceed the adjusted radial tension design value perpendicular to grain, f r F rt ', unless mechanical reinforcing sufficient to resist all radial stresses is used (see Reference 52). In no case shall f r exceed (1/3)F v '. 5.3.14 Format Conversion Factor, KF (LRFD only) For LRFD, reference design values shall be multiplied by the format conversion factor, K F, specified in Table 5.3.1. 5.3.15 Resistance Factor, (LRFD only) For LRFD, reference design values shall be multiplied by the resistance factor,, specified in Table 5.3.1. 5.3.16 Time Effect Factor, (LRFD only) For LRFD, reference design values shall be multiplied by the time effect factor, λ, specified in Appendix N.3.3. Where the bending moment is in the direction tending to increase curvature (decrease the radius), the radial stress shall not exceed the adjusted radial compression design, f r F rc '. 5.4.1.4 The deflection of curved bending members with constant cross section shall be determined in accordance with 3.5. Horizontal displacements at the supports shall also be considered. 5.4.2 Double-Tapered Curved Bending Members 5.4.2.1 The bending stress induced by a bending moment, M, at the peaked section of a double-tapered curved bending member (see Figure 5C) shall be calculated as follows: where: 6M f K (5.4-2) bd b 2 c K = empirical bending stress shape factor = 1 + 2.7 tant. T = angle of roof slope, degrees M = bending moment, in.-lbs dc = depth at peaked section of member, in. 5 STRUCTURAL GLUED LAMINATED TIMBER

40 STRUCTURAL GLUED LAMINATED TIMBER The stress interaction factor from 5.3.9 shall apply for flexural design in the straight-tapered segments of double-tapered curved bending members. 5.4.2.2 Double-tapered curved members shall be designed for shear strength in accordance with 3.4, except that the provisions of 3.4.3.1 shall not apply. The shear reduction factor from 5.3.10 shall apply. 5.4.2.3 The radial stress induced by bending moment in a double-tapered curved member shall be calculated as follows: where: 6M f KC (5.4-3) bd r rs rs 2 c Krs = empirical radial stress factor = 0.29(de/Rm) + 0.32 tan 1.2 T Crs = empirical load-shape radial stress reduction factor = 0.27 ln(tant) + 0.28 ln( / c) 0.8dc/Rm + 1 1.0 for uniformly loaded members where dc/rm 0.3 = 1.0 for members subject to constant moment = span length, in. 5.4.2.4 The deflection of double-tapered curved members shall be determined in accordance with 3.5, except that the mid-span deflection of a symmetrical double-tapered curved beam subject to uniform loads shall be permitted to be calculated by the following empirical formula: where: 5 ' 32Ε b d c 3 x equiv 4 c = vertical deflection at midspan, in. = uniformly distributed load, lbs/in. (5.4-4) dequiv = (de + dc)(0.5 + 0.735 tan T) -1.41dc tan B de = depth at the ends of the member, in. dc = depth at the peaked section of the member, in. T = angle of roof slope, degrees B = soffit slope at the ends of the member, degrees The horizontal deflection at the supports of symmetrical double-tapered curved beams shall be permitted to be estimated as: c = length between tangent points, in. M = bending moment, in.-lbs 2h H c (5.4-5) dc = depth at peaked section of member, in. Rm = radius of curvature at center line of member, in. = R + dc/2 R = radius of curvature of inside face of member, in. Where the bending moment is in the direction tending to decrease curvature (increase the radius), the radial stress shall not exceed the adjusted radial tension design value perpendicular to grain, f r F rt ', unless mechanical reinforcing sufficient to resist all radial stresses is used (see Reference 52). In no case shall f r exceed (1/3)F vx '. Where the bending moment is in the direction tending to increase curvature (decrease the radius), the radial stress shall not exceed the adjusted radial compression design value, f r F rc '. where: H = horizontal deflection at either support, in. h = ha dc/2 de/2 ha = /2 tant + de Figure 5C Double-Tapered Curved Bending Member T de B t c/2 c/2 t dt dc/2 P.T. R B hs Rm R P.T.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 41 5.4.3 Lateral Stability for Tudor Arches The ratio of tangent point depth to breadth (d/b) of tudor arches (see Figure 5D) shall not exceed 6, based on actual dimensions, when one edge of the arch is braced by decking fastened directly to the arch, or braced at frequent intervals as by girts or roof purlins. Where such lateral bracing is not present, d/b shall not exceed 5. Arches shall be designed for lateral stability in accordance with the provisions of 3.7 and 3.9.2. Figure 5D Tudor Arch the maximum deflection of a tapered straight beam subject to uniform loads shall be permitted to be calculated as equivalent to the depth, d equiv, of an equivalent prismatic member of the same width where: dequiv Cdtd e (5.4-6) where: de = depth at the small end of the member, in. Cdt = empirical constant derived from relationship of equations for deflection of tapered straight beams and prismatic beams. For symmetrical double-tapered beams: Cdt = 1 + 0.66Cy when 0 < Cy 1 5 5.4.4 Tapered Straight Bending Members 5.4.4.1 Tapered straight beams (see Figure 5E) shall be designed for flexural strength in accordance with 3.3. The stress interaction factor from 5.3.9 shall apply. For field-tapered members, the reference bending design value, F bx, and the reference modulus of elasticity, E x, shall be reduced according to the manufacturer s recommendations to account for the removal of high grade material near the surface of the member. 5.4.4.2 Tapered straight beams shall be designed for shear strength in accordance with 3.4, except that the provisions of 3.4.3.1 shall not apply. The shear reduction factor from 5.3.10 shall apply. 5.4.4.3 The deflection of tapered straight beams shall be determined in accordance with 3.5, except that Cdt = 1 + 0.62Cy when 0 < Cy 3 For single-tapered beams: Cdt = 1 + 0.46Cy when 0 < Cy 1.1 Cdt = 1 + 0.43Cy when 1.1 < Cy 2 For both single- and double-tapered beams: C d d d c e y e Figure 5E Tapered Straight Bending Members dc de L (a) dc de L (b) STRUCTURAL GLUED LAMINATED TIMBER

42 STRUCTURAL GLUED LAMINATED TIMBER 5.4.5 Notches 5.4.5.1 The tension side of structural glued laminated timber bending members shall not be notched, except at ends of members for bearing over a support, and notch depth shall not exceed the lesser of 1/10 the depth of the member or 3". 5.4.5.2 The compression side of structural glued laminated timber bending members shall not be notched, except at ends of members, and the notch depth on the compression side shall not exceed 2/5 the depth of the member. Compression side end-notches shall not extend into the middle 1/3 of the span. Exception: A taper cut on the compression edge at the end of a structural glued laminated timber bending member shall not exceed 2/3 the depth of the member and the length shall not exceed three times the depth of the member, 3d. For tapered beams where the taper extends into the middle 1/3 of the span, design shall be in accordance with 5.4.4. 5.4.5.3 Notches shall not be permitted on both the tension and compression face at the same crosssection. 5.4.5.4 See 3.1.2 and 3.4.3 for the effect of notches on strength. The shear reduction factor from 5.3.10 shall apply for the evaluation of members at notches.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 43 ROUND TIMBER POLES AND PILES 6.1 General 44 6.2 Reference Design Values 44 6.3 Adjustment of Reference Design Values 44 6 Table 6.3.1 Applicability of Adjustment Factors for Round Timber Poles and Piles...45 Table 6.3.5 Condition Treatment Factor, C t...45 Table 6.3.11 Load Sharing Factor, C ls, per ASTM D 2899...46

44 ROUND TIMBER POLES AND PILES 6.1 General 6.1.1 Scope 6.1.1.1 Chapter 6 applies to engineering design with round timber poles and piles. Design procedures and reference design values herein pertain to the load carrying capacity of poles and piles as structural wood members. 6.1.1.2 This Specification does not apply to the load supporting capacity of the soil. 6.1.2 Specifications 6.1.2.1 The procedures and reference design values herein apply only to timber piles conforming to applicable provisions of ASTM Standard D 25 and only to poles conforming to applicable provisions of ASTM Standard D 3200. 6.1.2.2 Specifications for round timber poles and piles shall include the standard for preservative treatment, pile length, and nominal tip circumference or nominal circumference 3 feet from the butt. Specifications for piles shall state whether piles are to be used as foundation piles, land and fresh water piles, or marine piles. 6.1.3 Standard Sizes 6.1.3.1 Standard sizes for round timber piles are given in ASTM Standard D 25. 6.1.3.2 Standard sizes for round timber poles are given in ASTM Standard D 3200. 6.1.4 Preservative Treatment 6.1.4.1 Reference design values apply to untreated, air dried timber poles and piles, and shall be adjusted in accordance with 6.3.5 when conditioned and treated by an approved process (see Reference 30). Load duration factors greater than 1.6 shall not apply to structural members pressure-treated with water-borne preservatives. 6.1.4.2 Untreated, timber poles and piles shall not be used unless the cutoff is below the lowest ground water level expected during the life of the structure, but in no case less than 3 feet below the existing ground water level unless approved by the authority having jurisdiction. 6.2 Reference Design Values 6.2.1 Reference Design Values 6.2.1.1 Reference design values for round timber piles are specified in Table 6A (published in the Supplement to this Specification). Reference design values in Table 6A are based on the provisions of ASTM Standard D 2899. 6.2.1.2 Reference design values for round timber poles are specified in Table 6B (published in the Supplement to this Specification). Reference design values in Table 6B are based on provisions of ASTM Standard D 3200. 6.2.2 Other Species or Grades Reference design values for piles of other species or grades shall be determined in accordance with ASTM Standard D 2899. 6.3 Adjustment of Reference Design Values 6.3.1 General 6.3.2 Load Duration Factor, CD (ASD Only) Reference design values (F c, F b, F v, F c, E, E min ) from Table 6A and 6B shall be multiplied by the adjustment factors specified in Table 6.3.1 to determine adjusted design values (F c ', F b ', F v ', F c ', E', E min '). All reference design values except modulus of elasticity, E, modulus of elasticity for column stability, E min, and compression perpendicular to grain, F c, shall be multiplied by load duration factors, C D, as specified in 2.3.2. Load duration factors greater than 1.6 shall not apply to timber poles or piles pressure-treated with wa-

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 45 Table 6.3.1 Applicability of Adjustment Factors for Round Timber Poles and Piles ASD only ASD and LRFD LRFD only Load Duration Factor Temperature Factor Condition Treatment Factor Size Factor Column Stability Factor Critical Section Factor Bearing Area Factor Load Sharing Factor Format Conversion Factor K F Resistance Factor Time Effect Factor F c ' = F c x C D C t C ct - C P C cs - C ls 2.40 0.90 F b ' = F b x C D C t C ct C F - - - C ls 2.54 0.85 6 F v ' = F v x C D C t C ct - - - - - 2.88 0.75 F c ' = F c x - C t C ct - - - C b - 1.67 0.90 - E ' = E x - C t - - - - - - - - - E min ' = E min x - C t - - - - - - 1.76 0.85 - ter-borne preservatives, (see Reference 30), nor to structural members pressure-treated with fire retardant chemicals (see Table 2.3.2). 6.3.3 Wet Service Factor, CM Reference design values apply to wet or dry service conditions (C M = 1.0). Table 6.3.5 Condition Treatment Factor, Cct Air Kiln Boulton Steaming Steaming Dried Dried Drying (Normal) (Marine) 1.0 0.90 0.95 0.80 0.74 6.3.6 Beam Stability Factor, CL ROUND TIMBER POLES AND PILES 6.3.4 Temperature Factor, Ct Reference design values shall be multiplied by temperature factors, C t, as specified in 2.3.3. 6.3.5 Condition Treatment Factor, Cct Reference design values are based on air dried conditioning. If kiln-drying, steam-conditioning, or boultonizing is used prior to treatment (see reference 20) then the reference design values shall be multiplied by the condition treatment factors, C ct, in Table 6.3.5. Reference bending design values, F b, for round timber poles or piles shall not be adjusted for beam stability. 6.3.7 Size Factor, CF Where pole or pile circumference exceeds 43" (diameter exceeds 13.5") at the critical section in bending, the reference bending design value, F b, shall be multiplied by the size factor, C F, specified in 4.3.6.2 and 4.3.6.3.

46 ROUND TIMBER POLES AND PILES 6.3.8 Column Stability Factor, CP Reference compression design values parallel to grain, F c, shall be multiplied by the column stability factor, C P, specified in 3.7 for the portion of a timber pole or pile standing unbraced in air, water, or material not capable of providing lateral support. 6.3.9 Critical Section Factor, Ccs Reference compression design values parallel to grain, F c, for round timber piles and poles are based on the strength at the tip of the pile. Reference compression design values parallel to grain, F c, in Table 6A and Table 6B shall be permitted to be multiplied by the critical section factor. The critical section factor, C cs, shall be determined as follows: where: Ccs = 1.0 + 0.004Lc (6.3-1) Lc = length from tip of pile to critical section, ft The increase for location of critical section shall not exceed 10% for any pile or pole (C cs 1.10). The critical section factors, C cs, are independent of tapered column provisions in 3.7.2 and both shall be permitted to be used in design calculations. 6.3.10 Bearing Area Factor, Cb Reference compression design values perpendicular to grain, F c, for timber poles or piles shall be permitted to be multiplied by the bearing area factor, C b, specified in 3.10.4. 6.3.11 Load Sharing Factor (Pile Group Factor), Cls group deforms as a single element when subjected to the load effects imposed on the element, reference bending design values, F b, and reference compression design values parallel to the grain, F c, shall be permitted to be multiplied by the load sharing factors, C ls, in Table 6.3.11. Table 6.3.11 Reference Design Value F c F b Load Sharing Factor, Cls, per ASTM D 2899 Number of Piles in Group 2 3 4 or more 2 3 4 or more C ls 1.06 1.09 1.11 1.05 1.07 1.08 6.3.12 Format Conversion Factor, KF (LRFD Only) For LRFD, reference design values shall be multiplied by the format conversion factor, K F, specified in Table 6.3.1. 6.3.13 Resistance Factor, (LRFD Only) For LRFD, reference design values shall be multiplied by the resistance factor,, specified in Table 6.3.1. 6.3.14 Time Effect Factor, (LRFD Only) For LRFD, reference design values shall be multiplied by the time effect factor,, specified in Appendix N.3.3. For piles, reference design values are based on single piles. If multiple piles are connected by concrete caps or equivalent force distributing elements so that the pile

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 47 PREFABRICATED WOOD I-JOISTS 7.1 General 48 7.2 Reference Design Values 48 7.3 Adjustment of Reference Design Values 48 7.4 Special Design Considerations 50 7 Table 7.3.1 Applicability of Adjustment Factors for Prefabricated Wood I-Joists... 49

48 PREFABRICATED WOOD I-JOISTS 7.1 General 7.1.1 Scope Chapter 7 applies to engineering design with prefabricated wood I-joists. Basic requirements are provided in this Specification. Design procedures and other information provided herein apply only to prefabricated wood I-joists conforming to all pertinent provisions of ASTM D 5055. 7.1.2 Definition The term prefabricated wood I-joist refers to a structural member manufactured using sawn or structural composite lumber flanges and wood structural panel webs bonded together with exterior exposure adhesives, forming an I cross-sectional shape. 7.1.3 Identification When the design procedures and other information provided herein are used, the prefabricated wood I-joists shall be identified with the manufacturer s name and the quality assurance agency s name. 7.1.4 Service Conditions Reference design values reflect dry service conditions, where the moisture content in service is less than 16%, as in most covered structures. Prefabricated wood I-joists shall not be used in higher moisture service conditions unless specifically permitted by the prefabricated wood I-joist manufacturer. 7.2 Reference Design Values Reference design values for prefabricated wood I-joists shall be obtained from the prefabricated wood I-joist manufacturer s literature or code evaluation reports. 7.3 Adjustment of Reference Design Values 7.3.1 General Reference design values (M r, V r, R r, EI, (EI) min, K) shall be multiplied by the adjustment factors specified in Table 7.3.1 to determine adjusted design values (M r ', V r ', R r ', EI', (EI) min ', K'). 7.3.2 Load Duration Factor, CD (ASD Only) All reference design values except stiffness, EI, (EI) min, and K, shall be multiplied by load duration factors, C D, as specified in 2.3.2. 7.3.3 Wet Service Factor, CM Reference design values for prefabricated wood I-joists are applicable to dry service conditions as specified in 7.1.4 where C M = 1.0. When the service conditions differ from the specified conditions, adjustments for high moisture shall be in accordance with information provided by the prefabricated wood I-joist manufacturer. 7.3.4 Temperature Factor, Ct When structural members will experience sustained exposure to elevated temperatures up to 150 F (see Appendix C), reference design values shall be multiplied by the temperature factors, C t, specified in 2.3.3. For M r, V r, R r, EI, (EI) min, and K use C t for F b, F v, F v, E, E min, and F v, respectively.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 49 Table 7.3.1 Applicability of Adjustment Factors for Prefabricated Wood I-Joists ASD only ASD and LRFD LRFD only Load Duration Factor Wet Service Factor Temperature Factor Beam Stability Factor Repetitive Member Factor Format Conversion Factor K F Resistance Factor φ Time Effect Factor M r ' = M r x C D C M C t C L C r K F 0.85 λ V r ' = V r x C D C M C t - - K F 0.75 λ R r ' = R r x C D C M C t - - K F 0.75 λ 7 7.3.5 Beam Stability Factor, CL EI ' = EI x - C M C t - - - - - (EI) min ' = (EI) min x - C M C t - - K F 0.85 - K ' = K x - C M C t - - - - - 7.3.5.1 Lateral stability of prefabricated wood I- joists shall be considered. 7.3.5.2 When the compression flange of a prefabricated wood I-joist is supported throughout its length to prevent lateral displacement, and the ends at points of bearing have lateral support to prevent rotation, C L =1.0. 7.3.5.3 When the compression flange of a prefabricated wood I-joist is not supported throughout its length to prevent lateral displacement, one acceptable method is to design the prefabricated wood I-joist compression flange as a column in accordance with the procedure of 3.7.1 using the section properties of the compression flange only. The compression flange shall be evaluated as a column continuously restrained from buckling in the plane of the web. C P of the compression flange shall be used as C L of the prefabricated wood I-joist. Prefabricated wood I-joists shall be provided with lateral support at points of bearing to prevent rotation. 7.3.6 Repetitive Member Factor, Cr For prefabricated wood I-joists with structural composite lumber flanges or sawn lumber flanges, reference moment design resistances shall be multiplied by the repetitive member factor, C r = 1.0. 7.3.7 Pressure-Preservative Treatment Adjustments to reference design values to account for the effects of pressure-preservative treatment shall be in accordance with information provided by the prefabricated wood I-joist manufacturer. PREFABRICATED WOOD I-JOISTS

50 PREFABRICATED WOOD I-JOISTS 7.3.8 Format Conversion Factor, KF (LRFD Only) For LRFD, reference design values shall be multiplied by the format conversion factor, K F, provided by the prefabricated wood I-joist manufacturer. 7.3.10 Time Effect Factor, λ (LRFD Only) For LRFD, reference design values shall be multiplied by the time effect factor, λ, specified in Appendix N.3.3. 7.3.9 Resistance Factor, φ (LRFD Only) For LRFD, reference design values shall be multiplied by the resistance factor, φ, specified in Table 7.3.1. 7.4 Special Design Considerations 7.4.1 Bearing Reference bearing design values, as a function of bearing length, for prefabricated wood I-joists with and without web stiffeners shall be obtained from the prefabricated wood I-joist manufacturer s literature or code evaluation reports. 7.4.2 Load Application Prefabricated wood I-joists act primarily to resist loads applied to the top flange. Web stiffener requirements, if any, at concentrated loads applied to the top flange and design values to resist concentrated loads applied to the web or bottom flange shall be obtained from the prefabricated wood I-joist manufacturer s literature or code evaluation reports. 7.4.3 Web Holes The effects of web holes on strength shall be accounted for in the design. Determination of critical shear at a web hole shall consider load combinations of 1.4.4 and partial span loadings defined as live or snow loads applied from each adjacent bearing to the opposite edge of a rectangular hole (centerline of a circular hole). The effects of web holes on deflection are negligible when the number of holes is limited to 3 or less per span. Reference design values for prefabricated wood I-joists with round or rectangular holes shall be obtained from the prefabricated wood I-joist manufacturer s literature or code evaluation reports. 7.4.4 Notches Notched flanges at or between bearings significantly reduces prefabricated wood I-joist capacity and is beyond the scope of this document. See the manufacturer for more information. 7.4.5 Deflection Both bending and shear deformations shall be considered in deflection calculations, in accordance with the prefabricated wood I-joist manufacturer s literature or code evaluation reports. 7.4.6 Vertical Load Transfer Prefabricated wood I-joists supporting bearing walls located directly above the prefabricated wood I- joist support require rim joists, blocking panels, or other means to directly transfer vertical loads from the bearing wall to the supporting structure below. 7.4.7 Shear Provisions of 3.4.3.1 for calculating shear force, V, shall not be used for design of prefabricated wood I-joist bending members.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 51 STRUCTURAL COMPOSITE LUMBER 8.1 General 52 8.2 Reference Design Values 52 8.3 Adjustment of Reference Design Values 52 8.4 Special Design Considerations 54 8 Table 8.3.1 Applicability of Adjustment Factors for Structural Composite Lumber... 53

52 STRUCTURAL COMPOSITE LUMBER 8.1 General 8.1.1 Scope Chapter 8 applies to engineering design with structural composite lumber. Basic requirements are provided in this Specification. Design procedures and other information provided herein apply only to structural composite lumber conforming to all pertinent provisions of ASTM D5456. 8.1.2 Definitions 8.1.2.1 The term laminated veneer lumber refers to a composite of wood veneer sheet elements with wood fiber primarily oriented along the length of the member. Veneer thickness shall not exceed 0.25". 8.1.2.2 The term parallel strand lumber refers to a composite of wood strand elements with wood fibers primarily oriented along the length of the member. The least dimension of the strands shall not exceed 0.25" and the average length shall be a minimum of 150 times the least dimension. 8.1.2.3 The term laminated strand lumber, refers to a composite of wood strand elements with wood fibers primarily oriented along the length of the member. The least dimension of the strands shall not exceed 0.10" and the average length shall be a minimum of 150 times the least dimension. 8.1.2.4 The term oriented strand lumber, refers to a composite of wood strand elements with wood fibers primarily oriented along the length of the member. The least dimension of the strands shall not exceed 0.10" and the average length shall be a minimum of 75 times the least dimension. 8.1.2.5 The term structural composite lumber refers to either laminated veneer lumber, parallel strand lumber, laminated strand lumber, or oriented strand lumber. These materials are structural members bonded with an exterior adhesive. 8.1.3 Identification When the design procedures and other information provided herein are used, the structural composite lumber shall be identified with the manufacturer s name and the quality assurance agency s name. 8.1.4 Service Conditions Reference design values reflect dry service conditions, where the moisture content in service is less than 16%, as in most covered structures. Structural composite lumber shall not be used in higher moisture service conditions unless specifically permitted by the structural composite lumber manufacturer. 8.2 Reference Design Values Reference design values for structural composite lumber shall be obtained from the structural composite lumber manufacturer s literature or code evaluation report. In special applications where deflection is a critical factor, or where deformation under long-term loading must be limited, the need for use of a reduced modulus of elasticity shall be determined. See Appendix F for provisions on adjusted values for special end use requirements. 8.3 Adjustment of Reference Design Values 8.3.1 General Reference design values (F b, F t, F v, F c, F c, E, E min ) shall be multiplied by the adjustment factors specified in Table 8.3.1 to determine adjusted design values (F b ', F t ', F v ', F c ', F c ', E', E min ').

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 53 Table 8.3.1 Applicability of Adjustment Factors for Structural Composite Lumber ASD only ASD and LRFD LRFD only Load Duration Factor Wet Service Factor Temperature Factor Beam Stability Factor 1 Volume Factor 1 Repetitive Member Factor Column Stability Factor Bearing Area Factor Format Conversion Factor K F Resistance Factor Time Effect Factor F b ' = F b x C D C M C t C L C V C r - - 2.54 0.85 F t ' = F t x C D C M C t - - - - - 2.70 0.80 F v ' = F v x C D C M C t - - - - - 2.88 0.75 F c ' = F c x C D C M C t - - - C P - 2.40 0.90 F c ' = F c x - C M C t - - - - C b 1.67 0.90 - E ' = E x - C M C t - - - - - - - - E min ' = E min x - C M C t - - - - - 1.76 0.85-1. See 8.3.6 for information on simultaneous application of the volume factor, C V, and the beam stability factor, C L. 8.3.2 Load Duration Factor, CD (ASD Only) All reference design values except modulus of elasticity, E, modulus of elasticity for beam and column stability, E min, and compression perpendicular to grain, F c, shall be multiplied by load duration factors, C D, as specified in 2.3.2. 8.3.3 Wet Service Factor, CM Reference design values for structural composite lumber are applicable to dry service conditions as specified in 8.1.4 where C M = 1.0. When the service conditions differ from the specified conditions, adjustments for high moisture shall be in accordance with information provided by the structural composite lumber manufacturer. 8.3.4 Temperature Factor, Ct When structural members will experience sustained exposure to elevated temperatures up to 150F (see Appendix C), reference design values shall be multiplied by the temperature factors, C t, specified in 2.3.3. 8.3.5 Beam Stability Factor, CL Structural composite lumber bending members shall be laterally supported in accordance with 3.3.3. 8.3.6 Volume Factor, CV Reference bending design values, F b, for structural composite lumber shall be multiplied by the volume factor, C V, and shall be obtained from the structural composite lumber manufacturer s literature or code evaluation reports. When C V 1.0, the volume factor, 8 STRUCTURAL COMPOSITE LUMBER

54 STRUCTURAL COMPOSITE LUMBER C V, shall not apply simultaneously with the beam stability factor, C L (see 3.3.3) and therefore, the lesser of these adjustment factors shall apply. When C V > 1.0, the volume factor, C V, shall apply simultaneously with the beam stability factor, C L (see 3.3.3). 8.3.7 Repetitive Member Factor, Cr Reference bending design values, F b, shall be multiplied by the repetitive member factor, C r = 1.04, where such members are used as joists, studs, or similar members which are in contact or spaced not more than 24" on center, are not less than 3 in number and are joined by floor, roof, or other load distributing elements adequate to support the design load. (A load distributing element is any adequate system that is designed or has been proven by experience to transmit the design load to adjacent members, spaced as described above, without displaying structural weakness or unacceptable deflection. Subflooring, flooring, sheathing, or other covering elements and nail gluing or tongue-andgroove joints, and through nailing generally meet these criteria.) 8.3.8 Column Stability Factor, CP Reference compression design values parallel to grain, F c, shall be multiplied by the column stability factor, C P, specified in 3.7. 8.3.9 Bearing Area Factor, Cb Reference compression design values perpendicular to grain, F c, shall be permitted to be multiplied by the bearing area factor, C b, as specified in 3.10.4. 8.3.10 Pressure-Preservative Treatment Adjustments to reference design values to account for the effects of pressure-preservative treatment shall be in accordance with information provided by the structural composite lumber manufacturer. 8.3.11 Format Conversion Factor, KF (LRFD Only) For LRFD, reference design values shall be multiplied by the format conversion factor, K F, specified in Table 8.3.1. 8.3.12 Resistance Factor, (LRFD Only) For LRFD, reference design values shall be multiplied by the resistance factor,, specified in Table 8.3.1. 8.3.13 Time Effect Factor, (LRFD Only) For LRFD, reference design values shall be multiplied by the time effect factor, λ, specified in Appendix N.3.3. 8.4 Special Design Considerations 8.4.1 Notches 8.4.1.1 The tension side of structural composite bending members shall not be notched, except at ends of members for bearing over a support, and notch depth shall not exceed 1/10 the depth of the member. The compression side of structural composite bending members shall not be notched, except at ends of members, and the notch depth on the compression side shall not exceed 2/5 the depth of the member. Compression side end-notches shall not extend into the middle third of the span. 8.4.1.2 See 3.1.2 and 3.4.3 for effect of notches on strength.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 55 WOOD STRUCTURAL PANELS 9.1 General 56 9.2 Reference Design Values 56 9.3 Adjustment of Reference Design Values 57 9.4 Design Considerations 58 9 Table 9.3.1 Applicability of Adjustment Factors for Wood Structural Panels... 57 Table 9.3.4 Panel Size Factor, C s... 58

56 WOOD STRUCTURAL PANELS 9.1 General 9.1.1 Scope Chapter 9 applies to engineering design with the following wood structural panels: plywood, oriented strand board, and composite panels. Basic requirements are provided in this Specification. Design procedures and other information provided herein apply only to wood structural panels complying with the requirements specified in this Chapter. 9.1.2 Identification 9.1.2.1 When design procedures and other information herein are used, the wood structural panel shall be identified for grade and glue type by the trademarks of an approved testing and grading agency. 9.1.2.2 Wood structural panels shall be specified by span rating, nominal thickness, exposure rating, and grade. 9.1.3 Definitions 9.1.3.1 The term wood structural panel refers to a wood-based panel product bonded with a waterproof adhesive. Included under this designation are plywood, oriented strand board (OSB) and composite panels. These panel products meet the requirements of USDOC PS 1 or PS 2 and are intended for structural use in residential, commercial, and industrial applications. 9.1.3.2 The term composite panel refers to a wood structural panel comprised of wood veneer and reconstituted wood-based material and bonded with waterproof adhesive. 9.1.3.3 The term oriented strand board refers to a mat-formed wood structural panel comprised of thin rectangular wood strands arranged in cross-aligned layers with surface layers normally arranged in the long panel direction and bonded with waterproof adhesive. 9.1.3.4 The term plywood refers to a wood structural panel comprised of plies of wood veneer arranged in cross-aligned layers. The plies are bonded with an adhesive that cures on application of heat and pressure. 9.1.4 Service Conditions 9.1.4.1 Reference design values reflect dry service conditions, where the moisture content in service is less than 16%, as in most covered structures. 9.2 Reference Design Values 9.2.1 Panel Stiffness and Strength 9.2.1.1 Reference panel stiffness and strength design values (the product of material and section properties) shall be obtained from an approved source. 9.2.1.2 Due to the orthotropic nature of panels, reference design values shall be provided for the primary and secondary strength axes. The appropriate reference design values shall be applied when designing for each panel orientation. When forces act at an angle to the principal axes of the panel, the capacity of the panel at the angle shall be calculated by adjusting the reference design values for the principal axes using principles of engineering mechanics. 9.2.3 Design Thickness Nominal thickness shall be used in design calculations. The relationships between span ratings and nominal thicknesses are provided with associated reference design values. 9.2.4 Design Section Properties Design section properties shall be assigned on the basis of span rating or design thickness and are provided on a per-foot-of-panel-width basis. 9.2.2 Strength and Elastic Properties Where required, strength and elastic parameters shall be calculated from reference strength and stiffness design values, respectively, on the basis of tabulated design section properties.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 57 9.3 Adjustment of Reference Design Values 9.3.1 General Reference design values shall be multiplied by the adjustment factors specified in Table 9.3.1 to determine adjusted design values. 9.3.2 Load Duration Factor, CD (ASD Only) All reference strength design values (F b S, F t A, F v t v, F s (Ib/Q), F c A) shall be multiplied by load duration factors, C D, as specified in 2.3.2. 9.3.3 Wet Service Factor, CM, and Temperature Factor, Ct Reference design values for wood structural panels are applicable to dry service conditions as specified in 9.1.4 where C M = 1.0 and C t = 1.0. When the service conditions differ from the specified conditions, adjustments for high moisture and/or high temperature shall be based on information from an approved source. Table 9.3.1 Applicability of Adjustment Factors for Wood Structural Panels ASD only ASD and LRFD LRFD only Load Duration Factor Wet Service Factor Temperature Factor Panel Size Factor Format Conversion Factor Resistance Factor Time Effect Factor F b S ' = F b S x C D C M C t C s 2.54 0.85 F t A ' = F t A x C D C M C t C s 2.70 0.80 ' F v t v = F v t v x C D C M C t - 2.88 0.75 F s (Ib/Q) ' = F s (Ib/Q) x C D C M C t - 2.88 0.75 F c A ' = F c A x C D C M C t - 2.40 0.90 ' F c = F c x - C M C t - 1.67 0.90 - EI ' = EI x - C M C t - - - - EA ' = EA x - C M C t - - - - ' G v t v = G v t v x - C M C t - - - - K F 9 WOOD STRUCTURAL PANELS

58 WOOD STRUCTURAL PANELS 9.3.4 Panel Size Factor, Cs Reference bending and tension design values (F b S and F t A) for wood structural panels are applicable to panels that are 24" or greater in width (i.e., dimension perpendicular to the applied stress). For panels less than 24" in width, reference bending and tension design values shall be multiplied by the panel size factor, C s, specified in Table 9.3.4. Table 9.3.4 Panel Size Factor, Cs Panel Strip Width, w C s w " 0.5 " w 24" (8 + w) / 32 w 24" 1.0 9.4 Design Considerations 9.4.1 Flatwise Bending 9.3.5 Format Conversion Factor, KF (LRFD Only) For LRFD, reference design values shall be multiplied by the format conversion factor, K F, specified in Table 9.3.1. 9.3.6 Resistance Factor, (LRFD Only) For LRFD, reference design values shall be multiplied by the resistance factor,, specified in Table 9.3.1. 9.3.7 Time Effect Factor, (LRFD Only) For LRFD, reference design values shall be multiplied by the time effect factor,, specified in Appendix N.3.3. 9.4.4 Planar (Rolling) Shear Wood structural panels shall be designed for flexure by checking bending moment, shear, and deflection. Adjusted planar shear shall be used as the shear resistance in checking the shear for panels in flatwise bending. Appropriate beam equations shall be used with the design spans as defined below. (a) Bending moment-distance between center-line of supports. (b) Shear-clear span. (c) Deflection-clear span plus the support width factor. For 2" nominal and 4" nominal framing, the support width factor is equal to 0.25" and 0.625", respectively. 9.4.2 Tension in the Plane of the Panel When wood structural panels are loaded in axial tension, the orientation of the primary strength axis of the panel with respect to the direction of loading, shall be considered in determining adjusted tensile capacity. 9.4.3 Compression in the Plane of the Panel When wood structural panels are loaded in axial compression, the orientation of the primary strength axis of the panel with respect to the direction of loading, shall be considered in determining the adjusted compressive capacity. In addition, panels shall be designed to prevent buckling. The adjusted planar (rolling) shear shall be used in design when the shear force is applied in the plane of wood structural panels. 9.4.5 Through-the-Thickness Shear The adjusted through-the-thickness shear shall be used in design when the shear force is applied throughthe-thickness of wood structural panels. 9.4.6 Bearing The adjusted bearing design value of wood structural panels shall be used in design when the load is applied perpendicular to the panel face.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 59 CROSS- LAMINATED TIMBER 10.1 General 60 10.2 Reference Design Values 60 10.3 Adjustment of Reference Design Values 60 10.4 Special Design Considerations 62 Table 10.3.1 Applicability of Adjustment Factors for Cross-Laminated Timber... 61 Table 10.4.1.1 Shear Deformation Adjustment Factors, K s... 62 10

60 CROSS-LAMINATED TIMBER 10.1 General 10.1.1 Application 10.1.1.1 Chapter 10 applies to engineering design with performance-rated cross-laminated timber. 10.1.1.2 Design procedures, reference design values and other information provided herein apply only to performance-rated cross-laminated timber produced in accordance with ANSI/APA PRG-320. 10.1.2 Definition Cross-Laminated Timber (CLT) a prefabricated engineered wood product consisting of at least three layers of solid-sawn lumber or structural composite lumber where the adjacent layers are cross-oriented and bonded with structural adhesive to form a solid wood element. 10.1.3 Standard Dimensions 10.1.3.1 The net thickness of a lamination for all layers at the time of gluing shall not be less than 5/8 inch or more than 2 inches. 10.1.3.2 The thickness of cross-laminated timber shall not exceed 20 inches. 10.1.4 Specification All required reference design values shall be specified in accordance with Section 10.2. 10.1.5 Service Conditions Reference design values reflect dry service conditions, where the moisture content in service is less than 16%, as in most covered structures. Cross-laminated timber shall not be used in higher moisture service conditions unless specifically permitted by the crosslaminated timber manufacturer. 10.2 Reference Design Values 10.2.1 Reference Design Values Reference design values for cross-laminated timber shall be obtained from the cross-laminated timber manufacturer s literature or code evaluation report. Reference design values shall be used with design section properties provided by the cross-laminated timber manufacturer based on the actual layup used in the manufacturing process. 10.2.2 Design Section Properties 10.3 Adjustment of Reference Design Values 10.3.1 General Reference design values: F b (S eff ), F t (A parallel ), F v (t v ), F s (Ib/Q) eff, F c (A parallel ), F c, (EI) app, and (EI) app-min provided in 10.2 shall be multiplied by the adjustment factors specified in Table 10.3.1 to determine adjusted design values: F b (S eff ), F t (A parallel ), F v (t v ), F s (Ib/Q) eff, F c (A parallel ), F c, (EI) app, and (EI) app-min. 10.3.2 Load Duration Factor, CD (ASD only) All reference design values except stiffness, (EI) app, (EI) app-min, rolling shear, F s (Ib/Q) eff, and compression perpendicular to grain, F c shall be multiplied by load duration factors, C D, as specified in 2.3.2.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 61 Table 10.3.1 Applicability of Adjustment Factors for Cross-Laminated Timber ASD only ASD and LRFD LRFD only Load Duration Factor Wet Service Factor Temperature Factor Beam Stability Factor Column Stability Factor Bearing Area Factor Format Conversion Factor Resistance Factor Time Effect Factor F b (S eff ) = F b (S eff ) x C D C M C t C L - - 2.54 0.85 F t (A parallel ) = F t (A parallel ) x C D C M C t - - - 2.70 F v (t v ) = F v (t v ) x C D C M C t - - - 2.88 0.75 F s (Ib/Q) eff = F s (Ib/Q) eff x - C M C t - - - 2.88 0.75 - F c (A parallel ) = F c (A parallel ) x C D C M C t - C P - 2.40 0.90 F c = F c x - C M C t - - C b 1.67 0.90 - (EI) app = (EI) app x - C M C t - - - - - - (EI) app-min = (EI) app-min x - C M C t - - - 1.76 0.85-10.3.3 Wet Service Factor, CM Reference design values for cross-laminated timber are applicable to dry service conditions as specified in 10.1.5 where C M = 1.0. When the service conditions differ from the specified conditions, adjustments for high moisture shall be in accordance with information provided by the cross-laminated timber manufacturer. 10.3.4 Temperature Factor, Ct When structural members will experience sustained exposure to elevated temperatures up to 150F (see Appendix C), reference design values shall be multiplied by the temperature factors, C t, specified in 2.3.3. 10.3.5 Curvature Factor, Cc The design of curved cross-laminated timber is beyond the scope of this standard. 10.3.6 Beam Stability Factor, CL Reference bending design values, F b (S eff ), shall be multiplied by the beam stability factor, C L, specified in 3.3.3. 10.3.7 Column Stability Factor, CP For cross-laminated timber loaded in-plane as a compression member, reference compression design values parallel to grain, F c (A parallel ), shall be multiplied by the column stability factor, C P, specified in 3.7. 10.3.8 Bearing Area Factor, Cb Reference compression design values perpendicular to grain, F c, shall be permitted to be multiplied by the bearing area factor, C b, as specified in 3.10.4. 10.3.9 Pressure-Preservative Treatment Reference design values apply to cross-laminated timber treated by an approved process and preservative (see Reference 30). Load duration factors greater than 10 CROSS-LAMINATED TIMBER

62 CROSS-LAMINATED TIMBER 1.6 shall not apply to structural members pressuretreated with water-borne preservatives. 10.3.10 Format Conversion Factor, KF (LRFD only) For LRFD, reference design values shall be multiplied by the format conversion factor, K F, specified in Table 10.3.1 10.3.11 Resistance Factor, (LRFD only) For LRFD, reference design values shall be multiplied by the resistance factor,, specified in Table 10.3.1. 10.3.12 Time Effect Factor, (LRFD only) For LRFD, reference design values shall be multiplied by the time effect factor, λ, specified in Appendix N.3.3. 10.4 Special Design Considerations 10.4.1 Deflection Table 10.4.1.1 Shear Deformation 10.4.1.1 Where reference design values for bending stiffness have not been adjusted to include the effects of shear deformation, the shear component of the total deflection of a cross-laminated timber element shall be determined in accordance with principles of engineering mechanics. One method of designing for shear deformation is to reduce the effective bending stiffness, (EI) eff, for the effects of shear deformation which is a function of loading and support conditions, beam geometry, span and the shear modulus. For the cases addressed in Table 10.4.1.1, the apparent bending stiffness, (EI) app, adjusted for shear deformation shall be calculated as follows: Adjustment Factors, Ks Loading End Fixity K s Uniformly Distributed Line Load at midspan Pinned Fixed Pinned Fixed 11.5 57.6 14.4 57.6 Line Load at quarter points Pinned 10.5 Constant Moment Pinned 11.8 Uniformly Distributed Cantilevered 4.8 Line Load at free-end Cantilevered 3.6 (E I) where: app EIeff 16K I 1 2 A L eff s eff (10.4-1) E = Reference modulus of elasticity, psi Ieff = Effective moment of inertia of the CLT section for calculating the bending stiffness of CLT, in. 4 /ft of panel width Ks = Shear deformation adjustment factor Aeff = Effective cross-sectional area of the CLT section for calculating the interlaminar shear capacity of CLT, in. 2 /ft of panel width L = Span of the CLT section, in.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 63 MECHANICAL CONNECTIONS 11.1 General 64 11.2 Reference Design Values 65 11.3 Adjustment of Reference Design Values 65 Table 11.3.1 Table 11.3.3 Table 11.3.4 Applicability of Adjustment Factors for Connections...66 Wet Service Factors, C M, for Connections...67 Temperature Factors, C t, for Connections...67 Table 11.3.6A Group Action Factors, C g, for Bolt or Lag Screw Connections with Wood Side Members...70 Table 11.3.6B Group Action Factors, C g, for 4" Split Ring or Shear Plate Connectors with Wood Side Members...70 Table 11.3.6C Group Action Factors, C g, for Bolt or Lag Screw Connections with Steel Side Plates...71 Table 11.3.6D Group Action Factors, C g, for 4" Shear Plate Connectors with Steel Side Plates...72 11

64 MECHANICAL CONNECTIONS 11.1 General 11.1.1 Scope 11.1.1.1 Chapter 11 applies to the engineering design of connections using bolts, lag screws, split ring connectors, shear plate connectors, drift bolts, drift pins, wood screws, nails, spikes, timber rivets, spike grids, or other fasteners in sawn lumber, structural glued laminated timber, timber poles, timber piles, structural composite lumber, prefabricated wood I- joists, wood structural panels, and cross-laminated timber. Except where specifically limited herein, the provisions of Chapter 11 shall apply to all fastener types covered in Chapters 12, 13, and 14. 11.1.1.2 The requirements of 3.1.3, 3.1.4, and 3.1.5 shall be accounted for in the design of connections. 11.1.1.3 Connection design provisions in Chapters 11, 12, 13, and 14 shall not preclude the use of connections where it is demonstrated by analysis based on generally recognized theory, full-scale or prototype loading tests, studies of model analogues or extensive experience in use that the connections will perform satisfactorily in their intended end uses (see 1.1.1.3). 11.1.2 Stresses in Members at Connections Structural members shall be checked for load carrying capacity at connections in accordance with all applicable provisions of this standard including 3.1.2, 3.1.3, and 3.4.3.3. Local stresses in connections using multiple fasteners shall be checked in accordance with principles of engineering mechanics. One method for determining these stresses is provided in Appendix E. 11.1.3 Eccentric Connections Eccentric connections that induce tension stress perpendicular to grain in the wood shall not be used unless appropriate engineering procedures or tests are employed in the design of such connections to insure that all applied loads will be safely carried by the members and connections. Connections similar to those in Figure 11A are examples of connections requiring appropriate engineering procedures or tests. 11.1.4 Mixed Fastener Connections Methods of analysis and test data for establishing reference design values for connections made with more than one type of fastener have not been developed. Reference design values and design value adjustments for mixed fastener connections shall be based on tests or other analysis (see 1.1.1.3). 11.1.5 Connection Fabrication Reference lateral design values for connections in Chapters 12, 13, and 14 are based on: (a) the assumption that the faces of the members are brought into contact when the fasteners are installed, and (b) allowance for member shrinkage due to seasonal variations in moisture content (see 11.3.3). Figure 11A Eccentric Connections

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 65 11.2 Reference Design Values 11.2.1 Single Fastener Connections 11.2.1.1 Chapters 12, 13, and 14 contain tabulated reference design values and design provisions for calculating reference design values for various types of single fastener connections. Reference design values for connections in a given species apply to all grades of that species unless otherwise indicated. Dowel-type fastener connection reference design values for one species of wood are also applicable to other species having the same or higher dowel bearing strength, F e. 11.2.1.2 Design provisions and reference design values for dowel-type fastener connections such as bolts, lag screws, wood screws, nails, spikes, drift bolts, and drift pins are provided in Chapter 12. 11.2.1.3 Design provisions and reference design values for split ring and shear plate connections are provided in Chapter 13. 11.2.1.4 Design provisions and reference design values for timber rivet connections are provided in Chapter 14. 11.2.1.5 Wood to wood connections involving spike grids for load transfer shall be designed in accordance with principles of engineering mechanics (see Reference 50 for additional information). 11.2.2 Multiple Fastener Connections Where a connection contains two or more fasteners of the same type and similar size, each of which exhibits the same yield mode (see Appendix I), the total adjusted design value for the connection shall be the sum of the adjusted design values for each individual fastener. Local stresses in connections using multiple fasteners shall be evaluated in accordance with principles of engineering mechanics (see 11.1.2). 11.2.3 Design of Metal Parts Metal plates, hangers, fasteners, and other metal parts shall be designed in accordance with applicable metal design procedures to resist failure in tension, shear, bearing (metal on metal), bending, and buckling (see References 39, 40, and 41). When the capacity of a connection is controlled by metal strength rather than wood strength, metal strength shall not be multiplied by the adjustment factors in this Specification. In addition, metal strength shall not be increased by wind and earthquake factors if design loads have already been reduced by load combination factors (see Reference 5 for additional information). 11.2.4 Design of Concrete or Masonry Parts Concrete footers, walls, and other concrete or masonry parts shall be designed in accordance with accepted practices (see References 1 and 2). When the capacity of a connection is controlled by concrete or masonry strength rather than wood strength, concrete or masonry strength shall not be multiplied by the adjustment factors in this Specification. In addition, concrete or masonry strength shall not be increased by wind and earthquake factors if design loads have already been reduced by load combination factors (see Reference 5 for additional information). MECHANICAL CONNECTIONS 11 11.3 Adjustment of Reference Design Values 11.3.1 Applicability of Adjustment Factors Reference design values (Z, W) shall be multiplied by all applicable adjustment factors to determine adjusted design values (Z', W'). Table 11.3.1 specifies the adjustment factors which apply to reference lateral design values (Z) and reference withdrawal design values (W) for each fastener type. The actual load applied to a connection shall not exceed the adjusted design value (Z', W') for the connection.

66 MECHANICAL CONNECTIONS Table 11.3.1 Applicability of Adjustment Factors for Connections ASD Only ASD and LRFD LRFD Only Load Duration Factor 1 Wet Service Factor Temperature Factor Lateral Loads Dowel-type Fasteners (e.g. bolts, lag screws, wood screws, nails, spikes, drift bolts, & drift pins) Z ' = Z x C D C M C t C g C - C eg - C di C tn 3.32 0.65 Split Ring and Shear Plate Connectors P ' = P x Q ' = Q x C D C D C M C M C t C t C g C g C C C d C d - - C st - - - - - 3.32 0.65 3.32 0.65 Timber Rivets P ' = P x C D C M C t - - - - 4 C st - - 3.32 0.65 Q ' = Q x C D C M C t - 5 C - - 4 C st - - 3.32 0.65 Spike Grids Z ' = Z x C D C M C t - C - - - - - 3.32 0.65 Nails, spikes, lag screws, wood screws, & drift pins W ' = W x C D C M 2 Group Action Factor Withdrawal Loads Geometry Factor 3 Penetration Depth Factor 3 End Grain Factor 3 Metal Side Plate Factor 3 C t - - - C eg - - C tn 3.32 0.65 1. The load duration factor, C D, shall not exceed 1.6 for connections (see 11.3.2). 2. The wet service factor, C M, shall not apply to toe-nails loaded in withdrawal (see 12.5.4.1). 3. Specific information concerning geometry factors C, penetration depth factors C d, end grain factors, C eg, metal side plate factors, C st, diaphragm factors, C di, and toe-nail factors, C tn, is provided in Chapters 12, 13, and 14. 4. The metal side plate factor, C st, is only applied when rivet capacity (P r, Q r) controls (see Chapter 14). 5. The geometry factor, C, is only applied when wood capacity, Q w, controls (see Chapter 14). Diaphragm Factor 3 Toe-Nail Factor 3 Format Conversion Factor K F Resistance Factor Time Effect Factor 11.3.2 Load Duration Factor, CD (ASD Only) Reference design values shall be multiplied by the load duration factors, C D 1.6, specified in 2.3.2 and Appendix B, except when the capacity of the connection is controlled by metal strength or strength of concrete/masonry (see 11.2.3, 11.2.4, and Appendix B.3). The impact load duration factor shall not apply to connections. 11.3.3 Wet Service Factor, CM Reference design values are for connections in wood seasoned to a moisture content of 19% or less and used under continuously dry conditions, as in most covered structures. For connections in wood that is unseasoned or partially seasoned, or when connections are exposed to wet service conditions in use, reference design values shall be multiplied by the wet service factors, C M, specified in Table 11.3.3. 11.3.4 Temperature Factor, Ct Reference design values shall be multiplied by the temperature factors, C t, in Table 11.3.4 for connections that will experience sustained exposure to elevated temperatures up to 150 F (see Appendix C).

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 67 Table 11.3.3 Wet Service Factors, CM, for Connections Fastener Type Moisture Content At Time of Fabrication In-Service C M Lateral Loads Split Ring and Shear Plate Connectors 1 19% > 19% any 19% 19% > 19% 1.0 0.8 0.7 Dowel-type Fasteners (e.g. bolts, lag screws, wood screws, nails, spikes, drift bolts, & drift pins) 19% > 19% any 19% 19% > 19% 1.0 0.4 2 0.7 Timber Rivets 19% 19% 19% > 19% 1.0 0.8 Lag Screws & Wood Screws any any Nails & Spikes 19% > 19% 19% > 19% Threaded Hardened Nails Withdrawal Loads 19% > 19% 19% 19% > 19% > 19% 1.0 0.7 1.0 0.25 0.25 1.0 any any 1.0 1. For split ring or shear plate connectors, moisture content limitations apply to a depth of 3/4" below the surface of the wood. 2 C M = 0.7 for dowel-type fasteners with diameter, D, less than 1/4". C M = 1.0 for dowel-type fastener connections with: 1) one fastener only, or 2) two or more fasteners placed in a single row parallel to grain, or 3) fasteners placed in two or more rows parallel to grain with separate splice plates for each row. MECHANICAL CONNECTIONS 11 Table 11.3.4 Temperature Factors, Ct, for Connections In-Service Moisture Conditions 1 C t T100F 100F<T125F 125F<T150F Dry 1.0 0.8 0.7 Wet 1.0 0.7 0.5 1. Wet and dry service conditions for connections are specified in 11.3.3. 11.3.5 Fire Retardant Treatment Adjusted design values for connections in lumber and structural glued laminated timber pressure-treated with fire retardant chemicals shall be obtained from the company providing the treatment and redrying service (see 2.3.4). The impact load duration factor shall not apply to connections in wood pressure-treated with fire retardant chemicals (see Table 2.3.2).

68 MECHANICAL CONNECTIONS 11.3.6 Group Action Factors, Cg 11.3.6.1 Reference lateral design values for split ring connectors, shear plate connectors, or dowel-type fasteners with D 1" in a row shall be multiplied by the following group action factor, C g : 2n m(1 m ) 1 REA Cg n 2n n 1 R 1 m EAm (1 m) 1 m where: (11.3-1) Cg = 1.0 for dowel type fasteners with D < 1/4" n = number of fasteners in a row EA s s EmAm REA = the lesser of or E A EA m m s s Em = modulus of elasticity of main member, psi Es = modulus of elasticity of side members, psi Am = gross cross-sectional area of main member, in. 2 As = sum of gross cross-sectional areas of side members, in. 2 2 m = u u 1 s 1 1 u = 1 2EmAm EA s s s = center to center spacing between adjacent fasteners in a row, in. = load/slip modulus for a connection, lbs/in. = 500,000 lbs/in. for 4" split ring or shear plate connectors = 400,000 lbs/in. for 2-1/2" split ring or 2-5/8" shear plate connectors = (180,000)(D 1.5 ) for dowel-type fasteners in wood-to-wood connections = (270,000)(D 1.5 ) for dowel-type fasteners in wood-to-metal connections D = diameter of dowel-type fastener, in. Group action factors for various connection geometries are provided in Tables 11.3.6A, 11.3.6B, 11.3.6C, and 11.3.6D. 11.3.6.2 For determining group action factors, a row of fasteners is defined as any of the following: (a) Two or more split rings or shear plate connector units, as defined in 13.1.1, aligned with the direction of load. (b) Two or more dowel-type fasteners of the same diameter loaded in single or multiple shear and aligned with the direction of load. Where fasteners in adjacent rows are staggered and the distance between adjacent rows is less than 1/4 the distance between the closest fasteners in adjacent rows measured parallel to the rows, the adjacent rows shall be considered as one row for purposes of determining group action factors. For groups of fasteners having an even number of rows, this principle shall apply to each pair of rows. For groups of fasteners having an odd number of rows, the most conservative interpretation shall apply (see Figure 11B). 11.3.6.3 Gross section areas shall be used, with no reductions for net section, when calculating A m and A s for determining group action factors. When a member is loaded perpendicular to grain its equivalent crosssectional area shall be the product of the thickness of the member and the overall width of the fastener group (see Figure 11B). Where only one row of fasteners is used, the width of the fastener group shall be the minimum parallel to grain spacing of the fasteners.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 69 Figure 11B Group Action for Staggered Fasteners Consider as 2 rows of 8 fasteners Consider as 1 row of 8 fasteners and 1 row of 4 fasteners MECHANICAL CONNECTIONS Consider as 1 row of 5 fasteners and 1 row of 3 fasteners 11 11.3.7 Format Conversion Factor, KF (LRFD Only) For LRFD, reference design values shall be multiplied by the format conversion factor, K F, specified in Table 11.3.1. 11.3.9 Time Effect Factor, (LRFD Only) For LRFD, reference design values shall be multiplied by the time effect factor,, specified in Appendix N.3.3. 11.3.8 Resistance Factor, (LRFD Only) For LRFD, reference design values shall be multiplied by the resistance factor,, specified in Table 11.3.1.

70 MECHANICAL CONNECTIONS Table 11.3.6A Group Action Factors, Cg, for Bolt or Lag Screw Connections with Wood Side Members 2 For D = 1", s = 4", E = 1,400,000 psi 1 A s /A m 1 A s Number of fasteners in a row in. 2 2 3 4 5 6 7 8 9 10 11 12 0.5 5 0.98 0.92 0.84 0.75 0.68 0.61 0.55 0.50 0.45 0.41 0.38 12 0.99 0.96 0.92 0.87 0.81 0.76 0.70 0.65 0.61 0.57 0.53 20 0.99 0.98 0.95 0.91 0.87 0.83 0.78 0.74 0.70 0.66 0.62 28 1.00 0.98 0.96 0.93 0.90 0.87 0.83 0.79 0.76 0.72 0.69 40 1.00 0.99 0.97 0.95 0.93 0.90 0.87 0.84 0.81 0.78 0.75 64 1.00 0.99 0.98 0.97 0.95 0.93 0.91 0.89 0.87 0.84 0.82 1 5 1.00 0.97 0.91 0.85 0.78 0.71 0.64 0.59 0.54 0.49 0.45 12 1.00 0.99 0.96 0.93 0.88 0.84 0.79 0.74 0.70 0.65 0.61 20 1.00 0.99 0.98 0.95 0.92 0.89 0.86 0.82 0.78 0.75 0.71 28 1.00 0.99 0.98 0.97 0.94 0.92 0.89 0.86 0.83 0.80 0.77 40 1.00 1.00 0.99 0.98 0.96 0.94 0.92 0.90 0.87 0.85 0.82 64 1.00 1.00 0.99 0.98 0.97 0.96 0.95 0.93 0.91 0.90 0.88 1. Where A s/a m > 1.0, use A m/a s and use A m instead of A s. 2. Tabulated group action factors (C g) are conservative for D < 1", s < 4", or E > 1,400,000 psi. Table 11.3.6B Group Action Factors, Cg, for 4" Split Ring or Shear Plate Connectors with Wood Side Members 2 s = 9", E = 1,400,000 psi 1 A s /A m 1 A s Number of fasteners in a row in. 2 2 3 4 5 6 7 8 9 10 11 12 0.5 5 0.90 0.73 0.59 0.48 0.41 0.35 0.31 0.27 0.25 0.22 0.20 12 0.95 0.83 0.71 0.60 0.52 0.45 0.40 0.36 0.32 0.29 0.27 20 0.97 0.88 0.78 0.69 0.60 0.53 0.47 0.43 0.39 0.35 0.32 28 0.97 0.91 0.82 0.74 0.66 0.59 0.53 0.48 0.44 0.40 0.37 40 0.98 0.93 0.86 0.79 0.72 0.65 0.59 0.54 0.49 0.45 0.42 64 0.99 0.95 0.91 0.85 0.79 0.73 0.67 0.62 0.58 0.54 0.50 1 5 1.00 0.87 0.72 0.59 0.50 0.43 0.38 0.34 0.30 0.28 0.25 12 1.00 0.93 0.83 0.72 0.63 0.55 0.48 0.43 0.39 0.36 0.33 20 1.00 0.95 0.88 0.79 0.71 0.63 0.57 0.51 0.46 0.42 0.39 28 1.00 0.97 0.91 0.83 0.76 0.69 0.62 0.57 0.52 0.47 0.44 40 1.00 0.98 0.93 0.87 0.81 0.75 0.69 0.63 0.58 0.54 0.50 64 1.00 0.98 0.95 0.91 0.87 0.82 0.77 0.72 0.67 0.62 0.58 1. Where A s/a m > 1.0, use A m/a s and use A m instead of A s. 2. Tabulated group action factors (C g) are conservative for 2-1/2" split ring connectors, 2-5/8" shear plate connectors, s < 9", or E > 1,400,000 psi.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 71 Table 11.3.6C Group Action Factors, Cg, for Bolt or Lag Screw Connections with Steel Side Plates 1 For D = 1", s = 4", E wood = 1,400,000 psi, E steel = 30,000,000 psi A m /A s A m Number of fasteners in a row in. 2 2 3 4 5 6 7 8 9 10 11 12 12 5 0.97 0.89 0.80 0.70 0.62 0.55 0.49 0.44 0.40 0.37 0.34 8 0.98 0.93 0.85 0.77 0.70 0.63 0.57 0.52 0.47 0.43 0.40 16 0.99 0.96 0.92 0.86 0.80 0.75 0.69 0.64 0.60 0.55 0.52 24 0.99 0.97 0.94 0.90 0.85 0.81 0.76 0.71 0.67 0.63 0.59 40 1.00 0.98 0.96 0.94 0.90 0.87 0.83 0.79 0.76 0.72 0.69 64 1.00 0.99 0.98 0.96 0.94 0.91 0.88 0.86 0.83 0.80 0.77 120 1.00 0.99 0.99 0.98 0.96 0.95 0.93 0.91 0.90 0.87 0.85 200 1.00 1.00 0.99 0.99 0.98 0.97 0.96 0.95 0.93 0.92 0.90 18 5 0.99 0.93 0.85 0.76 0.68 0.61 0.54 0.49 0.44 0.41 0.37 8 0.99 0.95 0.90 0.83 0.75 0.69 0.62 0.57 0.52 0.48 0.44 16 1.00 0.98 0.94 0.90 0.85 0.79 0.74 0.69 0.65 0.60 0.56 24 1.00 0.98 0.96 0.93 0.89 0.85 0.80 0.76 0.72 0.68 0.64 40 1.00 0.99 0.97 0.95 0.93 0.90 0.87 0.83 0.80 0.77 0.73 64 1.00 0.99 0.98 0.97 0.95 0.93 0.91 0.89 0.86 0.83 0.81 120 1.00 1.00 0.99 0.98 0.97 0.96 0.95 0.93 0.92 0.90 0.88 200 1.00 1.00 0.99 0.99 0.98 0.98 0.97 0.96 0.95 0.94 0.92 24 40 1.00 0.99 0.97 0.95 0.93 0.89 0.86 0.83 0.79 0.76 0.72 64 1.00 0.99 0.98 0.97 0.95 0.93 0.91 0.88 0.85 0.83 0.80 120 1.00 1.00 0.99 0.98 0.97 0.96 0.95 0.93 0.91 0.90 0.88 200 1.00 1.00 0.99 0.99 0.98 0.98 0.97 0.96 0.95 0.93 0.92 30 40 1.00 0.98 0.96 0.93 0.89 0.85 0.81 0.77 0.73 0.69 0.65 64 1.00 0.99 0.97 0.95 0.93 0.90 0.87 0.83 0.80 0.77 0.73 120 1.00 0.99 0.99 0.97 0.96 0.94 0.92 0.90 0.88 0.85 0.83 200 1.00 1.00 0.99 0.98 0.97 0.96 0.95 0.94 0.92 0.90 0.89 35 40 0.99 0.97 0.94 0.91 0.86 0.82 0.77 0.73 0.68 0.64 0.60 64 1.00 0.98 0.96 0.94 0.91 0.87 0.84 0.80 0.76 0.73 0.69 120 1.00 0.99 0.98 0.97 0.95 0.92 0.90 0.88 0.85 0.82 0.79 200 1.00 0.99 0.99 0.98 0.97 0.95 0.94 0.92 0.90 0.88 0.86 42 40 0.99 0.97 0.93 0.88 0.83 0.78 0.73 0.68 0.63 0.59 0.55 64 0.99 0.98 0.95 0.92 0.88 0.84 0.80 0.76 0.72 0.68 0.64 120 1.00 0.99 0.97 0.95 0.93 0.90 0.88 0.85 0.81 0.78 0.75 200 1.00 0.99 0.98 0.97 0.96 0.94 0.92 0.90 0.88 0.85 0.83 50 40 0.99 0.96 0.91 0.85 0.79 0.74 0.68 0.63 0.58 0.54 0.51 64 0.99 0.97 0.94 0.90 0.85 0.81 0.76 0.72 0.67 0.63 0.59 120 1.00 0.98 0.97 0.94 0.91 0.88 0.85 0.81 0.78 0.74 0.71 200 1.00 0.99 0.98 0.96 0.95 0.92 0.90 0.87 0.85 0.82 0.79 1. Tabulated group action factors (C g) are conservative for D < 1" or s < 4". MECHANICAL CONNECTIONS 11

72 MECHANICAL CONNECTIONS Table 11.3.6D Group Action Factors, Cg, for 4" Shear Plate Connectors with Steel Side Plates 1 s = 9", E wood = 1,400,000 psi, E steel = 30,000,000 psi A m /A s A m Number of fasteners in a row in. 2 2 3 4 5 6 7 8 9 10 11 12 12 5 0.91 0.75 0.60 0.50 0.42 0.36 0.31 0.28 0.25 0.23 0.21 8 0.94 0.80 0.67 0.56 0.47 0.41 0.36 0.32 0.29 0.26 0.24 16 0.96 0.87 0.76 0.66 0.58 0.51 0.45 0.40 0.37 0.33 0.31 24 0.97 0.90 0.82 0.73 0.64 0.57 0.51 0.46 0.42 0.39 0.35 40 0.98 0.94 0.87 0.80 0.73 0.66 0.60 0.55 0.50 0.46 0.43 64 0.99 0.96 0.91 0.86 0.80 0.74 0.69 0.63 0.59 0.55 0.51 120 0.99 0.98 0.95 0.91 0.87 0.83 0.79 0.74 0.70 0.66 0.63 200 1.00 0.99 0.97 0.95 0.92 0.89 0.85 0.82 0.79 0.75 0.72 18 5 0.97 0.83 0.68 0.56 0.47 0.41 0.36 0.32 0.28 0.26 0.24 8 0.98 0.87 0.74 0.62 0.53 0.46 0.40 0.36 0.32 0.30 0.27 16 0.99 0.92 0.82 0.73 0.64 0.56 0.50 0.45 0.41 0.37 0.34 24 0.99 0.94 0.87 0.78 0.70 0.63 0.57 0.51 0.47 0.43 0.39 40 0.99 0.96 0.91 0.85 0.78 0.72 0.66 0.60 0.55 0.51 0.47 64 1.00 0.97 0.94 0.89 0.84 0.79 0.74 0.69 0.64 0.60 0.56 120 1.00 0.99 0.97 0.94 0.90 0.87 0.83 0.79 0.75 0.71 0.67 200 1.00 0.99 0.98 0.96 0.94 0.91 0.89 0.86 0.82 0.79 0.76 24 40 1.00 0.96 0.91 0.84 0.77 0.71 0.65 0.59 0.54 0.50 0.46 64 1.00 0.98 0.94 0.89 0.84 0.78 0.73 0.68 0.63 0.58 0.54 120 1.00 0.99 0.96 0.94 0.90 0.86 0.82 0.78 0.74 0.70 0.66 200 1.00 0.99 0.98 0.96 0.94 0.91 0.88 0.85 0.82 0.78 0.75 30 40 0.99 0.93 0.86 0.78 0.70 0.63 0.57 0.52 0.47 0.43 0.40 64 0.99 0.96 0.90 0.84 0.78 0.71 0.66 0.60 0.56 0.51 0.48 120 0.99 0.98 0.94 0.90 0.86 0.81 0.76 0.71 0.67 0.63 0.59 200 1.00 0.98 0.96 0.94 0.91 0.87 0.83 0.79 0.76 0.72 0.68 35 40 0.98 0.91 0.83 0.74 0.66 0.59 0.53 0.48 0.43 0.40 0.36 64 0.99 0.94 0.88 0.81 0.73 0.67 0.61 0.56 0.51 0.47 0.43 120 0.99 0.97 0.93 0.88 0.82 0.77 0.72 0.67 0.62 0.58 0.54 200 1.00 0.98 0.95 0.92 0.88 0.84 0.80 0.76 0.71 0.68 0.64 42 40 0.97 0.88 0.79 0.69 0.61 0.54 0.48 0.43 0.39 0.36 0.33 64 0.98 0.92 0.84 0.76 0.69 0.62 0.56 0.51 0.46 0.42 0.39 120 0.99 0.95 0.90 0.85 0.78 0.72 0.67 0.62 0.57 0.53 0.49 200 0.99 0.97 0.94 0.90 0.85 0.80 0.76 0.71 0.67 0.62 0.59 50 40 0.95 0.86 0.75 0.65 0.56 0.49 0.44 0.39 0.35 0.32 0.30 64 0.97 0.90 0.81 0.72 0.64 0.57 0.51 0.46 0.42 0.38 0.35 120 0.98 0.94 0.88 0.81 0.74 0.68 0.62 0.57 0.52 0.48 0.45 200 0.99 0.96 0.92 0.87 0.82 0.77 0.71 0.66 0.62 0.58 0.54 1. Tabulated group action factors (C g) are conservative for 2-5/8" shear plate connectors or s < 9".

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 73 DOWEL-TYPE FASTENERS (BOLTS, LAG SCREWS, WOOD SCREWS, NAILS/SPIKES, DRIFT BOLTS, AND DRIFT PINS) 12.1 General 74 12.2 Reference Withdrawal Design Values 76 12.3 Reference Lateral Design Values 80 12.4 Combined Lateral and Withdrawal Loads 86 12.5 Adjustment of Reference Design Values 86 12.6 Multiple Fasteners 90 Table 12.2A Lag Screw Reference Withdrawal Design Values...77 Table 12.2B Wood Screw Reference Withdrawal Design Values...78 Table 12.2C Nail and Spike Reference Withdrawal Design Values...79 Table 12.2D Post-Frame Ring Shank Nail Reference Withdrawal Design Values...80 Table 12.3.1A Yield Limit Equations...81 Table 12.3.1B Reduction Term, R d...81 Table 12.3.3 Dowel Bearing Strengths...83 Table 12.3.3A Assigned Specific Gravities...84 Table 12.3.3B Dowel Bearing Strengths for Wood Structural Panels...85 Table 12.5.1A End Distance Requirements...87 Table 12.5.1B Spacing Requirements for Fasteners in a Row...87 Table 12.5.1C Edge Distance Requirements...88 Table 12.5.1D Spacing Requirements Between Rows...88 Table 12.5.1E Edge and End Distance and Spacing Requirements...88 Table 12.5.1F Perpendicular to Grain Distance Requirements...88 Table 12.5.1G End Distance, Edge Distance, and Fastener Spacing...89 Tables 12A-I BOLTS: Reference Lateral Design Values...92 Tables 12J-K LAG SCREWS: Reference Lateral Design Values...104 Tables 12L-M WOOD SCREWS: Reference Lateral Design Values...107 Tables 12N-T NAILS: Reference Lateral Values...109 12

74 DOWEL-TYPE FASTENERS 12.1 General 12.1.1 Scope Chapter 12 applies to the engineering design of connections using bolts, lag screws, wood screws, nails, spikes, drift bolts, drift pins, or other dowel-type fasteners in sawn lumber, structural glued laminated timber, timber poles, timber piles, structural composite lumber, prefabricated wood I-joists, wood structural panels, and cross-laminated timber. 12.1.2 Terminology 12.1.2.1 Edge distance is the distance from the edge of a member to the center of the nearest fastener, measured perpendicular to grain. When a member is loaded perpendicular to grain, the loaded edge shall be defined as the edge in the direction toward which the fastener is acting. The unloaded edge shall be defined as the edge opposite the loaded edge (see Figure 12G). 12.1.2.2 End distance is the distance measured parallel to grain from the square-cut end of a member to the center of the nearest bolt (see Figure 12G). 12.1.2.3 Spacing is the distance between centers of fasteners measured along a line joining their centers (see Figure 12G). 12.1.2.4 A row of fasteners is defined as two or more fasteners aligned with the direction of load (see Figure 12G). 12.1.2.5 End distance, edge distance, and spacing requirements herein are based on wood properties. Wood-to-metal and wood-to-concrete connections are subject to placement provisions as shown in 12.5.1, however, applicable end and edge distance and spacing requirements for metal and concrete, also apply (see 11.2.3 and 11.2.4). 12.1.3 Bolts 12.1.3.1 Installation requirements apply to bolts meeting requirements of ANSI/ASME Standard B18.2.1. See Appendix Table L1 for standard hex bolt dimensions. 12.1.3.2 Holes shall be a minimum of 1/32" to a maximum of 1/16" larger than the bolt diameter. Holes shall be accurately aligned in main members and side plates. Bolts shall not be forcibly driven. 12.1.3.3 A standard cut washer (Appendix Table L6), or metal plate or metal strap of equal or greater dimensions shall be provided between the wood and the bolt head and between the wood and the nut. 12.1.3.4 Edge distances, end distances, and fastener spacings shall not be less than the requirements in Tables 12.5.1A through 12.5.1D. 12.1.4 Lag Screws 12.1.4.1 Installation requirements apply to lag screws meeting requirements of ANSI/ASME Standard B18.2.1. See Appendix Table L2 for standard hex lag screw dimensions. 12.1.4.2 Lead holes for lag screws loaded laterally and in withdrawal shall be bored as follows to avoid splitting of the wood member during connection fabrication: (a) The clearance hole for the shank shall have the same diameter as the shank, and the same depth of penetration as the length of unthreaded shank. (b) The lead hole for the threaded portion shall have a diameter equal to 65% to 85% of the shank diameter in wood with G > 0.6, 60% to 75% in wood with 0.5 < G 0.6, and 40% to 70% in wood with G 0.5 (see Table 12.3.3A) and a length equal to at least the length of the threaded portion. The larger percentile in each range shall apply to lag screws of greater diameters. 12.1.4.3 Lead holes or clearance holes shall not be required for 3/8" and smaller diameter lag screws loaded primarily in withdrawal in wood with G 0.5 (see Table 12.3.3A), provided that edge distances, end distances, and spacing are sufficient to prevent unusual splitting. 12.1.4.4 The threaded portion of the lag screw shall be inserted in its lead hole by turning with a wrench, not by driving with a hammer. 12.1.4.5 No reduction to reference design values is anticipated if soap or other lubricant is used on the lag screw or in the lead holes to facilitate insertion and to prevent damage to the lag screw. 12.1.4.6 The minimum length of lag screw penetration, p min, not including the length of the tapered tip, E, of the lag screw into the main member of single shear connections and the side members of double shear connections shall be 4D. 12.1.4.7 Edge distances, end distances, and fastener spacings shall not be less than the requirements in Tables 12.5.1A through 12.5.1E.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 75 12.1.5 Wood Screws 12.1.5.1 Installation requirements apply to wood screws meeting requirements of ANSI/ASME Standard B18.6.1. See Appendix Table L3 for standard wood screw dimensions. 12.1.5.2 Lead holes for wood screws loaded in withdrawal shall have a diameter equal to approximately 90% of the wood screw root diameter in wood with G > 0.6, and approximately 70% of the wood screw root diameter in wood with 0.5 < G 0.6. Wood with G 0.5 (see Table 12.3.3A) is not required to have a lead hole for insertion of wood screws. 12.1.5.3 Lead holes for wood screws loaded laterally shall be bored as follows: (a) For wood with G > 0.6 (see Table 12.3.3A), the part of the lead hole receiving the shank shall have about the same diameter as the shank, and that receiving the threaded portion shall have about the same diameter as the screw at the root of the thread (see Reference 8). (b) For G 0.6 (see Table 12.3.3A), the part of the lead hole receiving the shank shall be about 7/8 the diameter of the shank and that receiving the threaded portion shall be about 7/8 the diameter of the screw at the root of the thread (see Reference 8). 12.1.5.4 The wood screw shall be inserted in its lead hole by turning with a screw driver or other tool, not by driving with a hammer. 12.1.5.5 No reduction to reference design values is anticipated if soap or other lubricant is used on the wood screw or in the lead holes to facilitate insertion and to prevent damage to the wood screw. 12.1.5.6 The minimum length of wood screw penetration, p min, including the length of the tapered tip where part of the penetration into the main member for single shear connections and the side members for double shear connections shall be 6D. 12.1.5.7 Edge distances, end distances, and fastener spacings shall be sufficient to prevent splitting of the wood. 12.1.6 Nails and Spikes 12.1.6.1 Installation requirements apply to common steel wire nails and spikes, box nails, threaded hardened-steel nails, and post-frame ring shank nails meeting requirements in ASTM F1667. Nail specifications for engineered construction shall include the minimum lengths and diameters for the nails and spikes to be used. See Appendix Table L4 for standard common, box, and sinker nail dimensions and Appendix Table L5 for standard post-frame ring shank nail dimensions. 12.1.6.2 Threaded, hardened-steel nails, and spikes shall be made of high carbon steel wire, headed, pointed, annularly or helically threaded, and heat-treated and tempered to provide greater yield strength than for common wire nails of corresponding size. 12.1.6.3 Reference design values herein apply to nailed and spiked connections either with or without bored holes. When a bored hole is desired to prevent splitting of wood, the diameter of the bored hole shall not exceed 90% of the nail or spike diameter for wood with G > 0.6, nor 75% of the nail or spike diameter for wood with G 0.6 (see Table 12.3.3A). 12.1.6.4 Toe-nails shall be driven at an angle of approximately 30 with the member and started approximately 1/3 the length of the nail from the member end (see Figure 12A). Figure 12A Toe-Nail Connection 12.1.6.5 The minimum length of nail or spike penetration, p min, including the length of the tapered tip where part of the penetration into the main member for single shear connections and the side members of double shear connections shall be 6D. Exception: The minimum length of penetration, p min, need not be 6D for symmetric double shear connections where nails with diameter of 0.148 or smaller extend at least three diameters beyond the side member and are clinched, and side members are at least 3/8" thick. 12.1.6.6 Edge distances, end distances, and fastener spacings shall be sufficient to prevent splitting of the wood. DOWEL-TYPE FASTENERS 12

76 DOWEL-TYPE FASTENERS 12.1.7 Drift Bolts and Drift Pins 12.1.7.1 Lead holes shall be drilled 0" to 1/32" smaller than the actual pin diameter. 12.1.7.2 Additional penetration of pin into members shall be provided in lieu of the washer, head, and nut on a common bolt (see Reference 53 for additional information). 12.1.7.3 Edge distances, end distances, and fastener spacings shall not be less than the requirements in Tables 12.5.1A through 12.5.1D. 12.1.8 Other Dowel-Type Fasteners Where fastener type or installation requirements vary from those specified in 12.1.3, 12.1.4, 12.1.5, 12.1.6, and 12.1.7, provisions of 12.2 and 12.3 shall be permitted to be used in the determination of reference withdrawal and lateral design values, respectively, provided allowance is made to account for such variation (see 11.1.1.3). Edge distances, end distances, and spacings shall be sufficient to prevent splitting of the wood. 12.2 Reference Withdrawal Design Values 12.2.1 Lag Screws 12.2.1.1 The lag screw reference withdrawal design value, W, in lbs/in. of thread penetration, for a single lag screw inserted in the side grain of a wood member, with the lag screw axis perpendicular to the wood fibers, shall be determined from Table 12.2A or Equation 12.2-1, within the range of specific gravities, G, and lag screw diameters, D, given in Table 12.2A. Reference withdrawal design values, W, shall be multiplied by all applicable adjustment factors (see Table 11.3.1) to obtain adjusted withdrawal design values, W'. W = 1800 G 3/2 D 3/4 (12.2-1) 12.2.1.2 For calculation of the fastener reference withdrawal design value in pounds, the unit reference withdrawal design value in lbs/in. of thread penetration from 12.2.1.1 shall be multiplied by the length of thread penetration, p t, into a wood member, excluding the length of the tapered tip. 12.2.1.3 Where lag screws are loaded in withdrawal from end grain, reference withdrawal design values, W, shall be multiplied by the end grain factor, C eg = 0.75. 12.2.1.4 Where lag screws are loaded in withdrawal, the tensile strength of the lag screw at the net section (root diameter, D r ) shall not be exceeded (see 11.2.3 and Appendix Table L2). 12.2.1.5 Where lag screws are loaded in withdrawal from the narrow edge of cross-laminated timber, the reference withdrawal value, W, shall be multiplied by the end grain factor, C eg =0.75, regardless of grain orientation. 12.2.2 Wood Screws 12.2.2.1 The wood screw reference withdrawal design value, W, in lbs/in. of thread penetration, for a single wood screw (cut thread or rolled thread) inserted in the side grain of a wood member, with the wood screw axis perpendicular to the wood fibers, shall be determined from Table 12.2B or Equation 12.2-2, within the range of specific gravities, G, and screw diameters, D, given in Table 12.2B. Reference withdrawal design values, W, shall be multiplied by all applicable adjustment factors (see Table 11.3.1) to obtain adjusted withdrawal design values, W'. W = 2850 G 2 D (12.2-2) 12.2.2.2 For calculation of the fastener reference withdrawal design value in pounds, the unit reference withdrawal design value in lbs/in. of thread penetration from 12.2.2.1 shall be multiplied by the length of thread penetration, p t, into the wood member. 12.2.2.3 Wood screws shall not be loaded in withdrawal from end grain of wood (C eg =0.0). 12.2.2.4 Wood screws shall not be loaded in withdrawal from end-grain of laminations in crosslaminated timber (C eg =0.0). 12.2.2.5 Where wood screws are loaded in withdrawal, the adjusted tensile strength of the wood screw at the net section (root diameter, D r ) shall not be exceeded (see 11.2.3 and Appendix Table L3). 12.2.3 Nails and Spikes 12.2.3.1 The nail or spike reference withdrawal design value, W, in lbs/in. of penetration, for a plain shank single nail or spike driven into the side grain of a wood member, with the nail or spike axis perpendicular to the wood fibers, shall be determined from Table 12.2C or Equation 12.2-3, within the range of specific gravities, G, and nail or spike diameters, D, given in Table 12.2C. Reference withdrawal design values, W, shall be multiplied by all applicable adjustment factors (see Table 11.3.1) to obtain adjusted withdrawal design values, W'. W = 1380 G 5/2 D (12.2-3)

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 77 Table 12.2A Lag Screw Reference Withdrawal Design Values, W 1 Tabulated withdrawal design values (W) are in pounds per inch of thread penetration into side grain of wood member. Length of thread penetration in main member shall not include the length of the tapered tip (see 12.2.1.1). Specific Gravity, G 2 Lag Screw Diameter, D 1/4" 5/16" 3/8" 7/16" 1/2" 5/8" 3/4" 7/8" 1" 1-1/8" 1-1/4" 0.73 397 469 538 604 668 789 905 1016 1123 1226 1327 0.71 381 450 516 579 640 757 868 974 1077 1176 1273 0.68 357 422 484 543 600 709 813 913 1009 1103 1193 0.67 349 413 473 531 587 694 796 893 987 1078 1167 0.58 281 332 381 428 473 559 641 719 795 869 940 0.55 260 307 352 395 437 516 592 664 734 802 868 0.51 232 274 314 353 390 461 528 593 656 716 775 0.50 225 266 305 342 378 447 513 576 636 695 752 0.49 218 258 296 332 367 434 498 559 617 674 730 0.47 205 242 278 312 345 408 467 525 580 634 686 0.46 199 235 269 302 334 395 453 508 562 613 664 0.44 186 220 252 283 312 369 423 475 525 574 621 0.43 179 212 243 273 302 357 409 459 508 554 600 0.42 173 205 235 264 291 344 395 443 490 535 579 0.41 167 198 226 254 281 332 381 428 473 516 559 0.40 161 190 218 245 271 320 367 412 455 497 538 0.39 155 183 210 236 261 308 353 397 438 479 518 0.38 149 176 202 227 251 296 340 381 422 461 498 0.37 143 169 194 218 241 285 326 367 405 443 479 0.36 137 163 186 209 231 273 313 352 389 425 460 0.35 132 156 179 200 222 262 300 337 373 407 441 0.31 110 130 149 167 185 218 250 281 311 339 367 1. Tabulated withdrawal design values, W, for lag screw connections shall be multiplied by all applicable adjustment factors (see Table 11.3.1). 2. Specific gravity, G, shall be determined in accordance with Table 12.3.3A. DOWEL-TYPE FASTENERS 12.2.3.2 For calculation of the fastener reference withdrawal design value in pounds, the unit reference withdrawal design value in lbs/in. of fastener penetration from 12.2.3.1 shall be multiplied by the length of fastener penetration, p t, into the wood member. 12.2.3.3 The reference withdrawal design value, in lbs/in. of penetration, for a single post-frame ring shank nail driven in the side grain of the main member, with the nail axis perpendicular to the wood fibers, shall be determined from Table 12.2D or Equation 12.2-4, within the range of specific gravities and nail diameters given in Table 12.2D. Reference withdrawal design values, W, shall be multiplied by all applicable adjustment factors (see Table 11.3.1) to obtain adjusted withdrawal design values, W'. W = 1800 G 2 D (12.2-4) 12.2.3.4 For calculation of the fastener reference withdrawal design value in pounds, the unit reference withdrawal design value in lbs/in. of ring shank penetration from 12.2.3.3 shall be multiplied by the length of ring shank penetration, p t, into the wood member. 12.2.3.5 Nails and spikes shall not be loaded in withdrawal from end grain of wood (C eg =0.0). 12.2.3.6 Nails, and spikes shall not be loaded in withdrawal from end-grain of laminations in crosslaminated timber (C eg =0.0). 12.2.4 Drift Bolts and Drift Pins Reference withdrawal design values, W, for connections using drift bolt and drift pin connections shall be determined in accordance with 11.1.1.3. 12

78 DOWEL-TYPE FASTENERS Table 12.2B Cut Thread or Rolled Thread Wood Screw Reference Withdrawal Design Values, W 1 Tabulated withdrawal design values, W, are in pounds per inch of thread penetration into side grain of wood member (see 12.2.2.1). Specific Wood Screw Number Gravity, 6 7 8 9 10 12 14 16 18 20 24 G 2 0.73 209 229 249 268 288 327 367 406 446 485 564 0.71 198 216 235 254 272 310 347 384 421 459 533 0.68 181 199 216 233 250 284 318 352 387 421 489 0.67 176 193 209 226 243 276 309 342 375 409 475 0.58 132 144 157 169 182 207 232 256 281 306 356 0.55 119 130 141 152 163 186 208 231 253 275 320 0.51 102 112 121 131 141 160 179 198 217 237 275 0.50 98 107 117 126 135 154 172 191 209 228 264 0.49 94 103 112 121 130 147 165 183 201 219 254 0.47 87 95 103 111 119 136 152 168 185 201 234 0.46 83 91 99 107 114 130 146 161 177 193 224 0.44 76 83 90 97 105 119 133 148 162 176 205 0.43 73 79 86 93 100 114 127 141 155 168 196 0.42 69 76 82 89 95 108 121 134 147 161 187 0.41 66 72 78 85 91 103 116 128 141 153 178 0.40 63 69 75 81 86 98 110 122 134 146 169 0.39 60 65 71 77 82 93 105 116 127 138 161 0.38 57 62 67 73 78 89 99 110 121 131 153 0.37 54 59 64 69 74 84 94 104 114 125 145 0.36 51 56 60 65 70 80 89 99 108 118 137 0.35 48 53 57 62 66 75 84 93 102 111 130 0.31 38 41 45 48 52 59 66 73 80 87 102 1. Tabulated withdrawal design values, W, for wood screw connections shall be multiplied by all applicable adjustment factors (see Table 11.3.1). 2. Specific gravity, G, shall be determined in accordance with Table 12.3.3A.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 79 Table 12.2C Nail and Spike Reference Withdrawal Design Values, W 1 Tabulated withdrawal design values, W, are in pounds per inch of fastenerpenetration into side grain of wood member (see 12.2.3.1). Threaded Nail Diameter, D Plain Shank Nail and Spike Diameter, D 0.099" 0.113" 0.128" 0.131" 0.135" 0.148" 0.162" 0.192" 0.207" 0.225" 0.244" 0.263" 0.283" 0.312" 0.375" 0.120" 0.135" 0.148" 0.177" 0.207" Specific Gravity, G 2 0.73 62 71 80 82 85 93 102 121 130 141 153 165 178 196 236 82 93 102 121 141 0.71 58 66 75 77 79 87 95 113 121 132 143 154 166 183 220 77 87 95 113 132 0.68 52 59 67 69 71 78 85 101 109 118 128 138 149 164 197 69 78 85 101 118 0.67 50 57 65 66 68 75 82 97 105 114 124 133 144 158 190 66 75 82 97 114 0.58 35 40 45 46 48 52 57 68 73 80 86 93 100 110 133 46 52 57 68 80 0.55 31 35 40 41 42 46 50 59 64 70 76 81 88 97 116 41 46 50 59 70 0.51 25 29 33 34 35 38 42 49 53 58 63 67 73 80 96 34 38 42 49 58 0.50 24 28 31 32 33 36 40 47 50 55 60 64 69 76 91 32 36 40 47 55 0.49 23 26 30 30 31 34 38 45 48 52 57 61 66 72 87 30 34 38 45 52 0.47 21 24 27 27 28 31 34 40 43 47 51 55 59 65 78 27 31 34 40 47 0.46 20 22 25 26 27 29 32 38 41 45 48 52 56 62 74 26 29 32 38 45 0.44 18 20 23 23 24 26 29 34 37 40 43 47 50 55 66 23 26 29 34 40 0.43 17 19 21 22 23 25 27 32 35 38 41 44 47 52 63 22 25 27 32 38 0.42 16 18 20 21 21 23 26 30 33 35 38 41 45 49 59 21 23 26 30 35 0.41 15 17 19 19 20 22 24 29 31 33 36 39 42 46 56 19 22 24 29 33 0.40 14 16 18 18 19 21 23 27 29 31 34 37 40 44 52 18 21 23 27 31 0.39 13 15 17 17 18 19 21 25 27 29 32 34 37 41 49 17 19 21 25 29 0.38 12 14 16 16 17 18 20 24 25 28 30 32 35 38 46 16 18 20 24 28 0.37 11 13 15 15 16 17 19 22 24 26 28 30 33 36 43 15 17 19 22 26 0.36 11 12 14 14 14 16 17 21 22 24 26 28 30 33 40 14 16 17 21 24 0.35 10 11 13 13 14 15 16 19 21 23 24 26 28 31 38 13 15 16 19 23 0.31 7 8 9 10 10 11 12 14 15 17 18 19 21 23 28 10 11 12 14 17 1. Tabulated withdrawal design values, W, for nail or spike connections shall be multiplied by all applicable adjustment factors (see Table 11.3.1). 2. Specific gravity, G, shall be determined in accordance with Table 12.3.3A. DOWEL-TYPE FASTENERS 12

80 DOWEL-TYPE FASTENERS Table 12.2D Post-Frame Ring Shank Nail Reference Withdrawal Design Values, W 1 Tabulated withdrawal design values, W, are in pounds per inch of ring shank penetration into side grain of wood member (see Appendix Table L5). Specific Gravity, G 2 Diameter, D (in.) 0.135 0.148 0.177 0.200 0.207 0.73 129 142 170 192 199 0.71 122 134 161 181 188 0.68 112 123 147 166 172 0.67 109 120 143 162 167 0.58 82 90 107 121 125 0.55 74 81 96 109 113 0.51 63 69 83 94 97 0.50 61 67 80 90 93 0.49 58 64 76 86 89 0.47 54 59 70 80 82 0.46 51 56 67 76 79 0.44 47 52 62 70 72 0.43 45 49 59 67 69 0.42 43 47 56 64 66 0.41 41 45 54 61 63 0.40 39 43 51 58 60 0.39 37 41 48 55 57 0.38 35 38 46 52 54 0.37 33 36 44 49 51 0.36 31 35 41 47 48 0.35 30 33 39 44 46 0.31 23 26 31 35 36 1. Tabulated withdrawal design values, W, for post-frame ring shank nails shall be multiplied by all applicable adjustment factors (see Table 11.3.1). 2. Specific gravity, G, shall be determined in accordance with Table 12.3.3A. 12.3 Reference Lateral Design Values 12.3.1 Yield Limit Equations Reference lateral design values, Z, for single shear and symmetric double shear connections using doweltype fasteners shall be the minimum computed yield mode value using equations in Tables 12.3.1A and 12.3.1B (see Figures 12B, 12C, and Appendix I) where: (a) the faces of the connected members are in contact; (b) the load acts perpendicular to the axis of the dowel; (c) edge distances, end distances, and spacing are not less than the requirements in 12.5; and (d) for lag screws, wood screws, and nails and spikes, the length of fastener penetration, p, into the main member of a single shear connection or the side member of a double shear connection is greater than or equal to p min (see 12.1). 12.3.2 Common Connection Conditions Reference lateral design values, Z, for connections with bolts (see Tables 12A through 12I), lag screws (see Tables 12J and 12K), wood screws (see Tables 12L and 12M), nails and spikes (see Tables 12N through 12R), and post-frame ring shank nails (see Tables 12S and 12T), are calculated for common connection conditions in accordance with yield mode equations in Tables 12.3.1A and 12.3.1B. Tabulated reference lateral design values, Z, shall be multiplied by applicable Table footnotes to determine an adjusted lateral design value, Z'.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 81 Table 12.3.1A Yield Limit Equations Yield Mode Single Shear Double Shear D m Fem D m Fem I m Z (12.3-1) Z R R Notes: k1 I s d d D s F Z R es k D F II Z 1 s es R III m III s IV d 2D (12.3-2) Z R (12.3-3) k2 D m Fem Z (12.3-4) (1 2R ) R e k D F Z (2 R ) R 3 s em 2 D 2Fem Fyb Z R 3 (1 R ) d 2 2 2 3 Re 2R e (1 Rt R t ) Rt Re R e(1 R t) e (1 R e ) 2 2F yb (1 2R e )D k2 1 2(1 R e) 2 3Fem m 2 2(1 R e ) 2F yb (2 R e )D k3 1 2 Re 3Fem s Table 12.3.1B Fastener Size d d e Reduction Term, Rd Yield Mode 0.25" D 1" I m, I s II III m, III s, IV 2k D F (12.3-5) Z (2 R ) R d d s F es 3 s em 2 2D 2Fem Fyb (12.3-6) Z R 3 (1 R ) Reduction Term, R d 4 K 3.6 K 3.2 K D < 0.25" I m, I s, II, III m, III s, IV K D 1 Notes: K = 1 + 0.25(/90) = maximum angle between the direction of load and the direction of grain (0 90 ) for any member in a connection D = diameter, in. (see 12.3.7) K D = 2.2 for D 0.17" K D = 10D + 0.5 for 0.17" < D < 0.25" 1. For threaded fasteners where nominal diameter (see Appendix L) is greater than or equal to 0.25" and root diameter is less than 0.25", R d = K D K. d e d e (12.3-7) (12.3-8) (12.3-9) (12.3-10) D = diameter, in. (see 12.3.7) F yb = dowel bending yield strength, psi R d = reduction term (see Table 12.3.1B) R e = F em /F es R t = m/ s m = main member dowel bearing length, in. s = side member dowel bearing length, in. F em = main member dowel bearing strength, psi (see Table 12.3.3) F es = side member dowel bearing strength, psi (see Table 12.3.3) 12.3.3 Dowel Bearing Strength 12.3.3.1 Dowel bearing strengths, F e, for wood members other than wood structural panels and structural composite lumber shall be determined from Table 12.3.3. 12.3.3.2 Dowel bearing strengths, F e, for doweltype fasteners with D 1/4" in wood structural panels shall be determined from Table 12.3.3B. 12.3.3.3 Dowel bearing strengths, F e, for structural composite lumber shall be determined from the manufacturer s literature or code evaluation report. 12.3.3.4 Where dowel-type fasteners with D 1/4" are inserted into the end grain of the main member, with the fastener axis parallel to the wood fibers, F e shall be used in the determination of the dowel bearing strength of the main member, F em. 12.3.3.5 Dowel bearing strengths, F e, for doweltype fasteners installed into the panel face of crosslaminated timber shall be based on the direction of DOWEL-TYPE FASTENERS 12

82 DOWEL-TYPE FASTENERS loading with respect to the grain orientation of the cross-laminated timber ply at the shear plane. 12.3.3.6 Where dowel-type fasteners are installed in the narrow edge of cross-laminated timber panels, the dowel bearing strength shall be F e for D1/4" and F e for D<1/4". Figure 12C Double Shear Bolted Connections 12.3.4 Dowel Bearing Strength at an Angle to Grain Where a member in a connection is loaded at an angle to grain, the dowel bearing strength, F e, for the member shall be determined as follows (see Appendix J): F where: FF e e e 2 2 Fe sin Fe cos (12.3-11) = angle between the direction of load and the direction of grain (longitudinal axis of member) 12.3.5 Dowel Bearing Length 12.3.5.1 Dowel bearing length in the side member(s) and main member, s and m, shall be determined based on the length of dowel bearing perpendicular to the application of load. 12.3.5.2 For cross-laminated timber where the direction of loading relative to the grain orientation at the shear plane is parallel to grain, the dowel bearing length in the perpendicular plies shall be reduced by multiplying the bearing length of those plies by the ratio of dowel bearing strength perpendicular to grain to dowel bearing strength parallel to grain (F e / F e ). Figure 12B Single Shear Bolted Connections 12.3.5.3 For lag screws, wood screws, nails, spikes, and similar dowel-type fasteners, the dowel bearing length, s or m, shall not exceed the length of fastener penetration, p, into the wood member. Where p includes the length of a tapered tip, E, the dowel bearing length, s or m, shall not exceed p - E/2. a) For lag screws, E is permitted to be taken from Appendix L, Table L2. b) For wood screws, nails, and spikes, E is permitted to be taken as 2D. 12.3.6 Dowel Bending Yield Strength 12.3.6.1 The reference lateral design values, Z, for bolts, lag screws, wood screws, and nails are based on dowel bending yield strengths, F yb, provided in Tables 12A through 12T. 12.3.6.2 Dowel bending yield strengths, F yb, used in the determination of reference lateral design values, Z, shall be based on yield strength derived using the methods provided in ASTM F 1575 or the tensile yield strength derived using the procedures of ASTM F 606. 12.3.7 Dowel Diameter 12.3.7.1 Where used in Tables 12.3.1A or 12.3.1B, the fastener diameter shall be taken as D for unthreaded full-body diameter fasteners and D r for reduced body diameter fasteners or threaded fasteners except as provided in 12.3.7.2. 12.3.7.2 For threaded full-body fasteners (see Appendix L), D shall be permitted to be used in lieu of D r where the bearing length of the threads does not exceed ¼ of the full bearing length in the member holding the threads. Alternatively, a more detailed analysis accounting for the moment and bearing resistance of the threaded portion of the fastener shall be permitted (see Appendix I).

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 83 Table 12.3.3 Dowel Bearing Strengths, Fe, for Dowel-Type Fasteners in Wood Members Specific 1 Dowel bearing strength in pounds per square inch (psi) 2 Gravity, F e F e F e G D<1/4" 1/4" D 1" D=1/4" D=5/16" D=3/8" D=7/16" D=1/2" D=5/8" D=3/4" D=7/8" D=1" 0.73 9300 8200 7750 6900 6300 5850 5450 4900 4450 4150 3850 0.72 9050 8050 7600 6800 6200 5750 5350 4800 4350 4050 3800 0.71 8850 7950 7400 6650 6050 5600 5250 4700 4300 3950 3700 0.70 8600 7850 7250 6500 5950 5500 5150 4600 4200 3900 3650 0.69 8400 7750 7100 6350 5800 5400 5050 4500 4100 3800 3550 0.68 8150 7600 6950 6250 5700 5250 4950 4400 4050 3750 3500 0.67 7950 7500 6850 6100 5550 5150 4850 4300 3950 3650 3400 0.66 7750 7400 6700 5950 5450 5050 4700 4200 3850 3550 3350 0.65 7500 7300 6550 5850 5350 4950 4600 4150 3750 3500 3250 0.64 7300 7150 6400 5700 5200 4850 4500 4050 3700 3400 3200 0.63 7100 7050 6250 5600 5100 4700 4400 3950 3600 3350 3100 0.62 6900 6950 6100 5450 5000 4600 4300 3850 3500 3250 3050 0.61 6700 6850 5950 5350 4850 4500 4200 3750 3450 3200 3000 0.60 6500 6700 5800 5200 4750 4400 4100 3700 3350 3100 2900 0.59 6300 6600 5700 5100 4650 4300 4000 3600 3300 3050 2850 0.58 6100 6500 5550 4950 4500 4200 3900 3500 3200 2950 2750 0.57 5900 6400 5400 4850 4400 4100 3800 3400 3100 2900 2700 0.56 5700 6250 5250 4700 4300 4000 3700 3350 3050 2800 2650 0.55 5550 6150 5150 4600 4200 3900 3650 3250 2950 2750 2550 0.54 5350 6050 5000 4450 4100 3750 3550 3150 2900 2650 2500 0.53 5150 5950 4850 4350 3950 3650 3450 3050 2800 2600 2450 0.52 5000 5800 4750 4250 3850 3550 3350 3000 2750 2550 2350 0.51 4800 5700 4600 4100 3750 3450 3250 2900 2650 2450 2300 0.50 4650 5600 4450 4000 3650 3400 3150 2800 2600 2400 2250 0.49 4450 5500 4350 3900 3550 3300 3050 2750 2500 2300 2150 0.48 4300 5400 4200 3750 3450 3200 3000 2650 2450 2250 2100 0.47 4150 5250 4100 3650 3350 3100 2900 2600 2350 2200 2050 0.46 4000 5150 3950 3550 3250 3000 2800 2500 2300 2100 2000 0.45 3800 5050 3850 3450 3150 2900 2700 2400 2200 2050 1900 0.44 3650 4950 3700 3300 3050 2800 2600 2350 2150 2000 1850 0.43 3500 4800 3600 3200 2950 2700 2550 2250 2050 1900 1800 0.42 3350 4700 3450 3100 2850 2600 2450 2200 2000 1850 1750 0.41 3200 4600 3350 3000 2750 2550 2350 2100 1950 1800 1650 0.40 3100 4500 3250 2900 2650 2450 2300 2050 1850 1750 1600 0.39 2950 4350 3100 2800 2550 2350 2200 1950 1800 1650 1550 0.38 2800 4250 3000 2700 2450 2250 2100 1900 1750 1600 1500 0.37 2650 4150 2900 2600 2350 2200 2050 1850 1650 1550 1450 0.36 2550 4050 2750 2500 2250 2100 1950 1750 1600 1500 1400 0.35 2400 3900 2650 2400 2150 2000 1900 1700 1550 1400 1350 0.34 2300 3800 2550 2300 2100 1950 1800 1600 1450 1350 1300 0.33 2150 3700 2450 2200 2000 1850 1750 1550 1400 1300 1200 0.32 2050 3600 2350 2100 1900 1750 1650 1500 1350 1250 1150 0.31 1900 3450 2250 2000 1800 1700 1600 1400 1300 1200 1100 1. Specific gravity, G, shall be determined in accordance with Table 12.3.3A. 2. F e = 11200G; F e = 6100G1.45 / D ; F e for D < 1/4" = 16600 G 1.84 ; Tabulated values are rounded to the nearest 50 psi. DOWEL-TYPE FASTENERS 12

84 DOWEL-TYPE FASTENERS Table 12.3.3A Assigned Specific Gravities Species Combination Specific 1 Gravity, G Alaska Cedar 0.47 Douglas Fir-Larch Species Combinations of MSR and MEL Lumber Specific 1 Gravity, G Alaska Hemlock 0.46 E=1,900,000 psi and lower grades of MSR 0.50 Alaska Spruce 0.41 E=2,000,000 psi grades of MSR 0.51 Alaska Yellow Cedar 0.46 E=2,100,000 psi grades of MSR 0.52 Aspen 0.39 E=2,200,000 psi grades of MSR 0.53 Balsam Fir 0.36 E=2,300,000 psi grades of MSR 0.54 Beech-Birch-Hickory 0.71 E=2,400,000 psi grades of MSR 0.55 Coast Sitka Spruce 0.39 Douglas Fir-Larch (North) Cottonwood 0.41 E=1,900,000 psi and lower grades of MSR and MEL 0.49 Douglas Fir-Larch 0.50 E=2,000,000 psi to 2,200,000 psi grades of MSR and MEL 0.53 Douglas Fir-Larch (North) 0.49 E=2,300,000 psi and higher grades of MSR and MEL 0.57 Douglas Fir-South 0.46 Douglas Fir-Larch (South) Eastern Hemlock 0.41 E=1,000,000 psi and higher grades of MSR 0.46 Eastern Hemlock-Balsam Fir 0.36 Engelmann Spruce-Lodgepole Pine Eastern Hemlock-Tamarack 0.41 E=1,400,000 psi and lower grades of MSR 0.38 Eastern Hemlock-Tamarack (North) 0.47 E=1,500,000 psi and higher grades of MSR 0.46 Eastern Softwoods 0.36 Hem-Fir Eastern Spruce 0.41 E=1,500,000 psi and lower grades of MSR 0.43 Eastern White Pine 0.36 E=1,600,000 psi grades of MSR 0.44 Engelmann Spruce-Lodgepole Pine 0.38 E=1,700,000 psi grades of MSR 0.45 Hem-Fir 0.43 E=1,800,000 psi grades of MSR 0.46 Hem-Fir (North) 0.46 E=1,900,000 psi grades of MSR 0.47 Mixed Maple 0.55 E=2,000,000 psi grades of MSR 0.48 Mixed Oak 0.68 E=2,100,000 psi grades of MSR 0.49 Mixed Southern Pine 0.51 E=2,200,000 psi grades of MSR 0.50 Mountain Hemlock 0.47 E=2,300,000 psi grades of MSR 0.51 Northern Pine 0.42 E=2,400,000 psi grades of MSR 0.52 Northern Red Oak 0.68 Hem-Fir (North) Northern Species 0.35 E=1,000,000 psi and higher grades of MSR and MEL 0.46 Northern White Cedar 0.31 Southern Pine Ponderosa Pine 0.43 E=1,700,000 psi and lower grades of MSR and MEL 0.55 Red Maple 0.58 E=1,800,000 psi and higher grades of MSR and MEL 0.57 Red Oak 0.67 Spruce-Pine-Fir Red Pine 0.44 E=1,700,000 psi and lower grades of MSR and MEL Redwood, close grain 0.44 E=1,800,000 psi and 1,900,000 grades of MSR and MEL Redwood, open grain 0.37 E=2,000,000 psi and higher grades of MSR and MEL Sitka Spruce 0.43 Spruce-Pine-Fir (South) Southern Pine 0.55 E=1,100,000 psi and lower grades of MSR 0.36 Spruce-Pine-Fir 0.42 E=1,200,000 psi to1,900,000 psi grades of MSR 0.42 Spruce-Pine-Fir (South) 0.36 E=2,000,000 psi and higher grades of MSR 0.50 Western Cedars 0.36 Western Cedars Western Cedars (North) 0.35 E=1,000,000 psi and higher grades of MSR 0.36 Western Hemlock 0.47 Western Woods Western Hemlock (North) 0.46 E=1,000,000 psi and higher grades of MSR 0.36 Western White Pine 0.40 Western Woods 0.36 White Oak 0.73 Yellow Poplar 0.43 1. Specific gravity, G, based on weight and volume when oven-dry. Different specific gravities, G, are possible for different grades of MSR and MEL lumber (see Table 4C, Footnote 2). 0.42 0.46 0.50

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 85 Table 12.3.3B Dowel Bearing Strengths for Wood Structural Panels Wood Structural Panel Specific 1 Gravity, G Plywood Structural 1, Marine 0.50 Other Grades 1 0.42 Dowel Bearing Strength, F e, in pounds per square inch (psi) for D 1/4" 4650 3350 Oriented Strand Board All Grades 0.50 4650 1. Use G = 0.42 when species of the plies is not known. When species of the plies is known, specific gravity listed for the actual species and the corresponding dowel bearing strength may be used, or the weighted average may be used for mixed species. 12.3.8 Asymmetric Three Member Connections, Double Shear Reference lateral design values, Z, for asymmetric three member connections shall be the minimum computed yield mode value for symmetric double shear connections using the smaller dowel bearing length in the side member as s and the minimum dowel diameter, D, occurring in either of the connection shear planes. 12.3.9 Multiple Shear Connections For a connection with four or more members (see Figure 12D), each shear plane shall be evaluated as a single shear connection. The reference lateral design value, Z, for the connection shall be the lowest reference lateral design value for any single shear plane, multiplied by the number of shear planes. Figure 12D Multiple Shear Bolted Connections 12.3.10 Load at an Angle to Fastener Axis 12.3.10.1 When the applied load in a single shear (two member) connection is at an angle (other than 90º) with the fastener axis, the fastener lengths in the two members shall be designated s and m (see Figure 12E). The component of the load acting at 90 with the fastener axis shall not exceed the adjusted lateral design value, Z', for a connection in which two members at 90 with the fastener axis have thicknesses t s = s and t m = m. Ample bearing area shall be provided to resist the load component acting parallel to the fastener axis. 12.3.10.2 For toe-nailed connections, the minimum of t s or L/3 shall be used for s (see Figure 12A). 12.3.11 Drift Bolts and Drift Pins Adjusted lateral design values, Z', for drift bolts and drift pins driven in the side grain of wood shall not exceed 75% of the adjusted lateral design values for common bolts of the same diameter and length in main member. Figure 12E Shear Area for Bolted Connections DOWEL-TYPE FASTENERS 12

86 DOWEL-TYPE FASTENERS 12.4 Combined Lateral and Withdrawal Loads 12.4.1 Lag Screws and Wood Screws Where a lag screw or wood screw is subjected to combined lateral and withdrawal loading, as when the fastener is inserted perpendicular to the fiber and the load acts at an angle,, to the wood surface (see Figure 12F), the adjusted design value, Z ', shall be determined as follows (see Appendix J): where: (W p)z Z (Wp)cos 2 Zsin 2 (12.4-1) where: (W p)z Z (Wp)cos Zsin Figure 12F = angle between the wood surface and the direction of applied load, degrees (12.4-2) p = length of fastener penetration into the main member, in. Combined Lateral and Withdrawal Loading = angle between the wood surface and the direction of applied load, degrees p = length of thread penetration into the main member, in. 12.4.2 Nails and Spikes Where a nail or spike is subjected to combined lateral and withdrawal loading, as when the nail or spike is inserted perpendicular to the fiber and the load acts at an angle,, to the wood surface, the adjusted design value, Z ', shall be determined as follows: 12.5 Adjustment of Reference Design Values 12.5.1 Geometry Factor, C 12.5.1.1 For dowel-type fasteners where D < 1/4", C = 1.0. 12.5.1.2 Where D 1/4" and the end distance or spacing provided for dowel-type fasteners is less than the minimum required for C = 1.0 for any condition in (a), (b), or (c), reference lateral design values, Z, shall be multiplied by the smallest applicable geometry factor, C, determined in (a), (b), or (c). The smallest geometry factor for any fastener in a group shall apply to all fasteners in the group. For multiple shear connections or for asymmetric three member connections, the smallest geometry factor, C, for any shear plane shall apply to all fasteners in the connection. (a) Where dowel-type fasteners are used and the actual end distance for parallel or perpendicular to grain loading is greater than or equal to the minimum end distance (see Table 12.5.1A) for C = 0.5, but less than the minimum end distance for C = 1.0, the geometry factor, C, shall be determined as follows: C = actual end distance minimum end distance for C = 1.0

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 87 Figure 12G Bolted Connection Geometry Table 12.5.1A End Distance Requirements Minimum end distance for C = 0.5 End Distances Minimum end distance for C = 1.0 Direction of Loading Perpendicular to Grain 2D 4D Parallel to Grain, Compression: (fastener bearing away from member end) 2D 4D Parallel to Grain, Tension: (fastener bearing toward member end) for softwoods for hardwoods 3.5D 2.5D 7D 5D (b) For loading at an angle to the fastener, where dowel-type fasteners are used, the minimum shear area for C = 1.0 shall be equivalent to the shear area for a parallel member connection with minimum end distance for C = 1.0 (see Table 12.5.1A and Figure 12E). The minimum shear area for C = 0.5 shall be equivalent to ½ the minimum shear area for C = 1.0. Where the actual shear area is greater than or equal to the minimum shear area for C = 0.5, but less than the minimum shear area for C = 1.0, the geometry factor, C, shall be determined as follows: C = actual shear area minimum shear area for C = 1.0 (c) Where the actual spacing between dowel-type fasteners in a row for parallel or perpendicular to grain loading is greater than or equal to the minimum spacing (see Table 12.5.1B), but less than the minimum spacing for C = 1.0, the geometry factor, C, shall be determined as follows: C = actual spacing minimum spacing for C = 1.0 12.5.1.3 Where D 1/4", edge distance and spacing between rows of fasteners shall be in accordance with Table 12.5.1C and Table 12.5.1D and applicable requirements of 12.1. The perpendicular to grain distance between the outermost fasteners shall not exceed 5" (see Figure 12H) unless special detailing is provided to accommodate cross-grain shrinkage of the wood member. For structural glued laminated timber members, the perpendicular to grain distance between the outermost fasteners shall not exceed the limits in Table 12.5.1F, unless special detailing is provided to accommodate cross-grain shrinkage of the member. 12.5.1.4 Where fasteners are installed in the narrow edge of cross-laminated timber panels and D 1/4", end distances, edge distances, and fastener spacing in a row shall not be less than the minimum values in Table 12.5.1G. Table 12.5.1B Spacing Requirements for Fasteners in a Row Spacing Direction of Loading Minimum spacing Minimum spacing for C = 1.0 Parallel to Grain 3D 4D Perpendicular to Grain 3D Required spacing for attached members DOWEL-TYPE FASTENERS 12

88 DOWEL-TYPE FASTENERS 12.5.2 End Grain Factor, Ceg 12.5.2.1 Where lag screws are loaded in withdrawal from end grain, the reference withdrawal design values, W, shall be multiplied by the end grain factor, C eg = 0.75. 12.5.2.2 Where dowel-type fasteners are inserted in the end grain of the main member, with the fastener axis parallel to the wood fibers, reference lateral design values, Z, shall be multiplied by the end grain factor, C eg = 0.67. 12.5.2.3 Where dowel-type fasteners with D1/4" are loaded laterally in the narrow edge of crosslaminated timber, the reference lateral design value, Z, shall be multiplied by the end grain factor, C eg =0.67, regardless of grain orientation. Table 12.5.1C Direction of Loading Parallel to Grain: where /D 6 where /D > 6 Perpendicular to Grain: 2 loaded edge unloaded edge Edge Distance Requirements 1,2 Minimum Edge Distance 1.5D 1.5D or ½ the spacing between rows, whichever is greater 4D 1.5D 1. The /D ratio used to determine the minimum edge distance shall be the lesser of: (a) length of fastener in wood main member/d = m/d (b) total length of fastener in wood side member(s)/d = s/d 2. Heavy or medium concentrated loads shall not be suspended below the neutral axis of a single sawn lumber or structural glued laminated timber beam except where mechanical or equivalent reinforcement is provided to resist tension stresses perpendicular to grain (see 3.8.2 and 11.1.3). Table 12.5.1D Spacing Requirements Between Rows 1 Direction of Loading Minimum Spacing Parallel to Grain 1.5D Perpendicular to Grain: where /D 2 2.5D where 2 < /D < 6 (5 + 10D) / 8 where /D 6 5D 1. The /D ratio used to determine the minimum edge distance shall be the lesser of: (a) length of fastener in wood main member/d = m/d (b) total length of fastener in wood side member(s)/d = s/d 12.5.3 Diaphragm Factor, Cdi Where nails or spikes are used in diaphragm construction, reference lateral design values, Z, are permitted to be multiplied by the diaphragm factor, C di = 1.1. 12.5.4 Toe-Nail Factor, Ctn 12.5.4.1 Reference withdrawal design values, W, for toe-nailed connections shall be multiplied by the toe-nail factor, C tn = 0.67. The wet service factor, C M, shall not apply. 12.5.4.2 Reference lateral design values, Z, for toe-nailed connections shall be multiplied by the toenail factor, C tn = 0.83. Table 12.5.1E Orientation Edge Distance End Distance Spacing Table 12.5.1F Fastener Type Edge and End Distance and Spacing Requirements for Lag Screws Loaded in Withdrawal and Not Loaded Laterally Minimum Distance/Spacing 1.5D 4D 4D Perpendicular to Grain Distance Requirements for Outermost Fasteners in Structural Glued Laminated Timber Members Moisture Content At Time of Fabrication In- Service Maximum Distance Between Outer Rows All Fasteners >16% <16% 5" Any >16% 5" Bolts <16% <16% 10" Lag Screws <16% <16% 6" Drift Pins <16% <16% 6"

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 89 Table 12.5.1G End Distance, Edge Distance and Fastener Spacing Requirements in Narrow Edge of Cross-Laminated Timber (see Figure 12 ) Figure 12 End Distance, Edge Distance and Fastener Spacing Requirements in Narrow Edge of Cross-Laminated Timber Direction of Loading Minimum End Distance Minimum Edge Distance Minimum Spacing for Fasteners in a Row Perpendicular to Plane of CLT 4D Parallel to Plane of CLT, Compression: (fastener bearing away from member end) 4D 3D 4D Parallel to Plane of CLT, Tension: (fastener bearing toward member end) 7D Figure 12H Spacing Between Outer Rows of Bolts DOWEL-TYPE FASTENERS 12

90 DOWEL-TYPE FASTENERS 12.6 Multiple Fasteners 12.6.1 Symmetrically Staggered Fasteners Where a connection contains multiple fasteners, fasteners shall be staggered symmetrically in members loaded perpendicular to grain whenever possible (see 11.3.6.2 for special design provisions where bolts, lag screws, or drift pins are staggered). 12.6.3 Local Stresses in Connections Local stresses in connections using multiple fasteners shall be evaluated in accordance with principles of engineering mechanics (see 11.1.2). 12.6.2 Fasteners Loaded at an Angle to Grain When a multiple fastener connection is loaded at an angle to grain, the gravity axis of each member shall pass through the center of resistance of the group of fasteners to insure uniform stress in the main member and a uniform distribution of load to all fasteners.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 91 This page left blank intentionally. DOWEL-TYPE FASTENERS 12

92 DOWEL-TYPE FASTENERS BOLTS Table 12A Thickness Main Member Side Member Bolt Diameter BOLTS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections 1,2 for sawn lumber or SCL with both members of identical specific gravity G=0.67 Red Oak G=0.55 Mixed Maple Southern Pine G=0.50 Douglas Fir-Larch G=0.49 Douglas Fir-Larch(N) G=0.46 Douglas Fir(S) Hem-Fir(N) t m t s D Z ll Z s Z m Z Z ll Z s Z m Z Z ll Z s Z m Z Z ll Z s Z m Z Z ll Z s Z m Z in. in. in. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. 1/2 650 420 420 330 530 330 330 250 480 300 300 220 470 290 290 210 440 270 270 190 5/8 810 500 500 370 660 400 400 280 600 360 360 240 590 350 350 240 560 320 320 220 1-1/2 1-1/2 3/4 970 580 580 410 800 460 460 310 720 420 420 270 710 400 400 260 670 380 380 240 7/8 1130 660 660 440 930 520 520 330 850 470 470 290 830 460 460 280 780 420 420 250 1 1290 740 740 470 1060 580 580 350 970 530 530 310 950 510 510 300 890 480 480 280 1/2 760 490 490 390 620 390 390 290 560 350 350 250 550 340 340 250 520 320 320 230 5/8 940 590 590 430 770 470 470 330 700 420 420 280 690 410 410 280 650 380 380 250 1-3/4 1-3/4 3/4 1130 680 680 480 930 540 540 360 850 480 480 310 830 470 470 300 780 440 440 280 7/8 1320 770 770 510 1080 610 610 390 990 550 550 340 970 530 530 320 910 500 500 300 1 1510 860 860 550 1240 680 680 410 1130 610 610 360 1110 600 600 350 1040 560 560 320 1/2 770 480 540 440 660 400 420 350 610 370 370 310 610 360 360 300 580 340 330 270 5/8 1070 660 630 520 930 560 490 390 850 520 430 340 830 520 420 330 780 470 390 300 2-1/2 1-1/2 3/4 1360 890 720 570 1120 660 560 430 1020 590 500 380 1000 560 480 360 940 520 450 330 7/8 1590 960 800 620 1300 720 620 470 1190 630 550 410 1170 600 540 390 1090 550 500 360 1 1820 1020 870 660 1490 770 680 490 1360 680 610 440 1330 650 590 420 1250 600 550 390 1/2 770 480 560 440 660 400 470 360 610 370 430 330 610 360 420 320 580 340 400 310 5/8 1070 660 760 590 940 560 620 500 880 520 540 460 870 520 530 450 830 470 490 410 1-1/2 3/4 1450 890 900 770 1270 660 690 580 1200 590 610 510 1190 560 590 490 1140 520 550 450 7/8 1890 960 990 830 1680 720 770 630 1590 630 680 550 1570 600 650 530 1470 550 600 480 1 2410 1020 1080 890 2010 770 830 670 1830 680 740 590 1790 650 710 560 1680 600 660 520 1/2 830 510 590 480 720 420 510 390 670 380 470 350 660 380 460 340 620 360 440 320 5/8 1160 680 820 620 1000 580 640 520 930 530 560 460 920 530 550 450 880 500 510 410 3-1/2 1-3/4 3/4 1530 900 940 780 1330 770 720 580 1250 680 640 520 1240 660 620 500 1190 600 580 460 7/8 1970 1120 1040 840 1730 840 810 640 1620 740 710 550 1590 700 690 530 1490 640 640 490 1 2480 1190 1130 900 2030 890 880 670 1850 790 780 590 1820 750 760 570 1700 700 700 530 1/2 830 590 590 530 750 520 520 460 720 490 490 430 710 480 480 420 690 460 460 410 5/8 1290 880 880 780 1170 780 780 650 1120 700 700 560 1110 690 690 550 1070 650 650 500 3-1/2 3/4 1860 1190 1190 950 1690 960 960 710 1610 870 870 630 1600 850 850 600 1540 800 800 560 7/8 2540 1410 1410 1030 2170 1160 1160 780 1970 1060 1060 680 1940 1040 1040 650 1810 980 980 590 1 3020 1670 1670 1100 2480 1360 1360 820 2260 1230 1230 720 2210 1190 1190 690 2070 1110 1110 640 5/8 1070 660 760 590 940 560 640 500 880 520 590 460 870 520 590 450 830 470 560 430 1-1/2 3/4 1450 890 990 780 1270 660 850 660 1200 590 790 590 1190 560 780 560 1140 520 740 520 7/8 1890 960 1260 960 1680 720 1060 720 1590 630 940 630 1570 600 900 600 1520 550 830 550 1 2410 1020 1500 1020 2150 770 1140 770 2050 680 1010 680 2030 650 970 650 1930 600 910 600 5/8 1160 680 820 620 1000 580 690 520 930 530 630 470 920 530 630 470 880 500 590 440 5-1/4 1-3/4 3/4 1530 900 1050 800 1330 770 890 680 1250 680 830 630 1240 660 810 620 1190 600 780 590 7/8 1970 1120 1320 1020 1730 840 1090 840 1640 740 960 740 1620 700 920 700 1550 640 850 640 1 2480 1190 1530 1190 2200 890 1170 890 2080 790 1040 790 2060 750 1000 750 1990 700 930 700 5/8 1290 880 880 780 1170 780 780 680 1120 700 730 630 1110 690 720 620 1070 650 690 580 3-1/2 3/4 1860 1190 1240 1080 1690 960 1090 850 1610 870 1030 780 1600 850 1010 750 1540 800 970 710 7/8 2540 1410 1640 1260 2300 1160 1380 1000 2190 1060 1230 870 2170 1040 1190 840 2060 980 1100 770 1 3310 1670 1940 1420 2870 1390 1520 1060 2660 1290 1360 940 2630 1260 1320 900 2500 1210 1230 830 5/8 1070 660 760 590 940 560 640 500 880 520 590 460 870 520 590 450 830 470 560 430 1-1/2 3/4 1450 890 990 780 1270 660 850 660 1200 590 790 590 1190 560 780 560 1140 520 740 520 7/8 1890 960 1260 960 1680 720 1090 720 1590 630 980 630 1570 600 940 600 1520 550 860 550 5-1/2 1 2410 1020 1560 1020 2150 770 1190 770 2050 680 1060 680 2030 650 1010 650 1930 600 940 600 5/8 1290 880 880 780 1170 780 780 680 1120 700 730 630 1110 690 720 620 1070 650 690 580 3-1/2 3/4 1860 1190 1240 1080 1690 960 1090 850 1610 870 1030 780 1600 850 1010 750 1540 800 970 710 7/8 2540 1410 1640 1260 2300 1160 1410 1020 2190 1060 1260 910 2170 1040 1220 870 2060 980 1130 790 1 3310 1670 1980 1470 2870 1390 1550 1100 2660 1290 1390 970 2630 1260 1340 930 2500 1210 1250 860 5/8 1070 660 760 590 940 560 640 500 880 520 590 460 870 520 590 450 830 470 560 430 1-1/2 3/4 1450 890 990 780 1270 660 850 660 1200 590 790 590 1190 560 780 560 1140 520 740 520 7/8 1890 960 1260 960 1680 720 1090 720 1590 630 1010 630 1570 600 990 600 1520 550 950 550 7-1/2 1 2410 1020 1560 1020 2150 770 1350 770 2050 680 1270 680 2030 650 1240 650 1930 600 1190 600 5/8 1290 880 880 780 1170 780 780 680 1120 700 730 630 1110 690 720 620 1070 650 690 580 3-1/2 3/4 1860 1190 1240 1080 1690 960 1090 850 1610 870 1030 780 1600 850 1010 750 1540 800 970 710 7/8 2540 1410 1640 1260 2300 1160 1450 1020 2190 1060 1360 930 2170 1040 1340 900 2060 980 1280 850 1 3310 1670 2090 1470 2870 1390 1830 1210 2660 1290 1630 1110 2630 1260 1570 1080 2500 1210 1470 1030 1. Tabulated lateral design values, Z, for bolted connections shall be multiplied by all applicable adjustment factors (see Table 11.3.1). 2. Tabulated lateral design values, Z, are for full-body diameter bolts (see Appendix Table L1) with bolt bending yield strength, F yb, of 45,000 psi.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 93 Table 12A (Cont.) Thickness Main Member Side Member Bolt Diameter BOLTS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections 1,2 for sawn lumber or SCL with both members of identical specific gravity G=0.43 Hem-Fir G=0.42 Spruce-Pine-Fir G=0.37 Redwood (open grain) G=0.36 Eastern Softwoods Spruce-Pine-Fir(S), Western Cedars, Western Woods G=0.35 Northern Species BOLTS t m t s D Z ll Z s Z m Z Z ll Z s Z m Z Z ll Z s Z m Z Z ll Z s Z m Z Z ll Z s Z m Z in. in. in. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. 1/2 410 250 250 180 410 240 240 170 360 210 210 140 350 200 200 130 340 200 200 130 5/8 520 300 300 190 510 290 290 190 450 250 250 160 440 240 240 150 420 240 240 150 1-1/2 1-1/2 3/4 620 350 350 210 610 340 340 210 540 290 290 170 520 280 280 170 500 270 270 160 7/8 720 390 390 230 710 380 380 220 630 330 330 190 610 320 320 180 590 310 310 170 1 830 440 440 250 810 430 430 240 720 370 370 200 700 360 360 190 670 350 350 190 1/2 480 290 290 210 470 280 280 200 420 250 250 170 410 240 240 160 390 230 230 150 5/8 600 350 350 230 590 340 340 220 520 290 290 190 510 280 280 180 490 270 270 170 1-3/4 1-3/4 3/4 720 400 400 250 710 390 390 240 630 340 340 200 610 330 330 190 590 320 320 190 7/8 850 460 460 270 830 450 450 260 730 390 390 220 710 380 380 210 690 360 360 200 1 970 510 510 290 950 500 500 280 840 430 430 230 820 420 420 230 790 410 410 220 1/2 550 320 310 250 540 320 300 240 500 290 250 200 490 280 240 190 470 280 240 180 5/8 730 420 360 270 710 410 350 270 630 350 300 220 610 330 290 210 590 320 280 210 2-1/2 1-1/2 3/4 870 460 410 300 850 450 400 290 750 370 340 240 740 360 330 230 710 350 320 230 7/8 1020 500 450 320 1000 490 440 310 880 410 380 260 860 390 370 250 830 370 350 240 1 1160 540 500 350 1140 530 490 340 1010 440 420 280 980 420 410 270 940 410 390 260 1/2 550 320 380 290 540 320 370 280 500 290 320 250 490 280 300 250 480 280 290 240 5/8 790 420 440 370 780 410 430 360 720 350 370 300 710 330 350 290 700 320 340 280 1-1/2 3/4 1100 460 500 400 1080 450 480 390 1010 370 410 320 990 360 400 310 950 350 380 300 7/8 1370 500 550 430 1340 490 540 420 1180 410 460 350 1160 390 440 340 1110 370 420 320 1 1570 540 600 470 1530 530 590 460 1350 440 500 380 1320 420 480 370 1270 410 470 350 1/2 590 340 400 300 580 330 390 290 530 300 330 260 520 290 320 250 510 280 310 250 5/8 840 480 460 370 820 470 450 360 760 400 390 310 740 380 370 290 730 370 360 280 3-1/2 1-3/4 3/4 1130 540 520 410 1120 530 510 400 1030 430 430 330 1000 420 420 320 970 410 410 310 7/8 1390 580 580 440 1360 570 570 430 1200 470 480 360 1170 460 470 350 1130 430 440 320 1 1590 630 640 480 1550 610 630 460 1370 510 530 380 1340 490 520 370 1290 470 500 360 1/2 660 440 440 390 660 430 430 380 620 400 400 330 610 390 390 310 600 380 380 310 5/8 1040 600 600 450 1020 590 590 440 960 520 520 370 950 500 500 350 930 490 490 340 3-1/2 3/4 1450 740 740 500 1420 730 730 480 1250 650 650 400 1220 630 630 390 1180 620 620 370 7/8 1690 910 910 540 1660 890 890 520 1460 770 770 440 1430 750 750 420 1370 720 720 390 1 1930 1030 1030 580 1890 1000 1000 560 1670 870 870 470 1630 840 840 450 1570 810 810 430 5/8 790 420 530 410 780 410 520 400 720 350 470 350 710 330 460 330 700 320 450 320 1-1/2 3/4 1100 460 690 460 1080 450 670 450 1010 370 560 370 990 360 540 360 970 350 530 350 7/8 1460 500 750 500 1440 490 730 490 1350 410 620 410 1330 390 600 390 1280 370 560 370 1 1800 540 820 540 1760 530 800 530 1560 440 670 440 1520 420 650 420 1460 410 630 410 5/8 840 480 560 410 820 470 550 410 760 400 500 370 740 380 480 360 730 370 470 350 5-1/4 1-3/4 3/4 1130 540 700 540 1120 530 680 530 1040 430 570 430 1020 420 560 420 1000 410 540 410 7/8 1490 580 770 580 1470 570 750 570 1370 470 640 470 1350 460 620 460 1320 430 580 430 1 1910 630 850 630 1890 610 820 610 1760 510 690 510 1740 490 670 490 1700 470 650 470 5/8 1040 600 660 530 1020 590 650 520 960 520 610 460 950 500 590 440 930 490 580 430 3-1/2 3/4 1490 740 900 640 1480 730 880 620 1390 650 750 520 1370 630 730 500 1330 620 710 480 7/8 1950 920 1010 690 1920 910 990 670 1740 820 850 560 1710 800 830 550 1660 770 780 510 1 2370 1140 1130 750 2330 1120 1100 730 2120 1020 940 600 2080 980 910 580 2030 950 880 560 5/8 790 420 530 410 780 410 520 400 720 350 470 350 710 330 460 330 700 320 450 320 1-1/2 3/4 1100 460 700 460 1080 450 690 450 1010 370 580 370 990 360 570 360 970 350 550 350 7/8 1460 500 780 500 1440 490 760 490 1350 410 650 410 1330 390 630 390 1280 370 590 370 5-1/2 1 1800 540 860 540 1760 530 830 530 1560 440 700 440 1520 420 680 420 1460 410 650 410 5/8 1040 600 660 530 1020 590 650 520 960 520 610 460 950 500 590 440 930 490 580 430 3-1/2 3/4 1490 740 920 650 1480 730 900 640 1390 650 770 530 1370 630 750 520 1330 620 720 500 7/8 1950 920 1030 720 1920 910 1010 700 1740 820 870 590 1710 800 840 570 1660 770 800 530 1 2370 1140 1150 780 2330 1120 1120 760 2120 1020 960 630 2080 980 930 600 2030 950 890 580 5/8 790 420 530 410 780 410 520 400 720 350 470 350 710 330 460 330 700 320 450 320 1-1/2 3/4 1100 460 700 460 1080 450 690 450 1010 370 630 370 990 360 620 360 970 350 600 350 7/8 1460 500 900 500 1440 490 890 490 1350 410 810 410 1330 390 800 390 1280 370 770 370 7-1/2 1 1800 540 1130 540 1760 530 1110 530 1560 440 920 440 1520 420 890 420 1460 410 860 410 5/8 1040 600 660 530 1020 590 650 520 960 520 610 460 950 500 590 440 930 490 580 430 3-1/2 3/4 1490 740 920 650 1480 730 910 640 1390 650 840 560 1370 630 820 550 1330 620 810 540 7/8 1950 920 1210 790 1920 910 1180 780 1740 820 1010 700 1710 800 980 680 1660 770 920 650 1 2370 1140 1340 970 2330 1120 1300 950 2120 1020 1100 820 2080 980 1070 790 2030 950 1030 760 1. Tabulated lateral design values, Z, for bolted connections shall be multiplied by all applicable adjustment factors (see Table 11.3.1). 2. Tabulated lateral design values, Z, are for full-body diameter bolts (see Appendix Table L1) with bolt bending yield strength, F yb, of 45,000 psi. DOWEL-TYPE FASTENERS 12

94 DOWEL-TYPE FASTENERS BOLTS Table 12B Thickness Main Member Side Member Bolt Diameter BOLTS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections 1,2 for sawn lumber or SCL main member with 1/4" ASTM A 36 steel side plate G=0.67 Red Oak G=0.55 Mixed Maple Southern Pine G=0.50 Douglas Fir-Larch G=0.49 Douglas Fir-Larch(N) G=0.46 Douglas Fir(S) Hem-Fir(N) G=0.43 Hem-Fir G=0.42 Spruce-Pine-Fir G=0.37 Redwood (open grain) G=0.36 Eastern Softwoods Spruce-Pine-Fir(S) Western Cedars Western Woods G=0.35 Northern Species t m t s D Z ll Z Z ll Z Z ll Z Z ll Z Z ll Z Z ll Z Z ll Z Z ll Z Z ll Z Z ll Z in. in. in. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. 1/2 730 420 620 350 580 310 580 310 550 290 520 280 510 270 470 240 460 240 450 230 5/8 910 480 780 400 730 360 720 360 690 340 650 320 640 320 590 290 580 280 560 270 1-1/2 1/4 3/4 1090 550 940 450 870 420 860 410 820 390 780 360 770 360 710 320 690 320 680 310 7/8 1270 600 1090 510 1020 470 1010 450 960 430 910 410 900 400 820 370 810 360 790 350 1 1460 660 1250 550 1170 510 1150 500 1100 480 1040 450 1030 450 940 400 930 400 900 390 1/2 810 460 690 370 640 340 630 330 600 310 570 290 560 280 510 250 500 250 490 240 5/8 1020 520 870 430 800 390 790 380 750 360 710 340 700 330 640 300 630 290 610 280 1-3/4 1/4 3/4 1220 590 1040 480 960 440 950 430 900 410 860 380 840 370 770 330 750 330 730 320 7/8 1420 650 1210 540 1130 490 1110 480 1050 450 1000 420 980 420 890 380 880 370 850 360 1 1630 710 1380 580 1290 540 1270 520 1200 500 1140 470 1120 460 1020 410 1000 410 980 400 1/2 930 600 860 470 830 410 820 400 780 380 740 350 720 340 650 300 640 290 620 280 5/8 1370 670 1150 530 1050 470 1040 470 980 430 920 400 910 390 810 340 800 330 770 320 2-1/2 1/4 3/4 1640 750 1370 590 1270 530 1250 520 1180 490 1110 450 1090 440 980 380 960 370 930 360 7/8 1910 820 1600 650 1480 590 1450 570 1370 530 1290 490 1270 480 1140 420 1120 410 1080 400 1 2190 880 1830 700 1690 640 1660 620 1570 580 1480 540 1450 530 1300 460 1280 450 1240 440 1/2 930 620 860 550 830 510 820 510 800 480 770 450 770 430 720 370 720 360 710 350 5/8 1370 860 1260 690 1210 610 1200 600 1160 550 1130 500 1120 490 1060 420 1050 410 1020 400 3-1/2 1/4 3/4 1900 990 1740 760 1670 680 1660 660 1580 610 1480 560 1450 540 1290 460 1260 450 1220 440 7/8 2530 1070 2170 840 1990 740 1950 710 1840 660 1720 610 1690 590 1510 510 1480 500 1430 470 1 2980 1150 2480 890 2270 800 2230 770 2100 730 1970 660 1930 650 1720 560 1690 540 1630 530 5/8 1370 860 1260 760 1210 710 1200 700 1160 670 1130 640 1120 630 1060 580 1050 560 1030 540 5-1/4 1/4 3/4 1900 1140 1740 1000 1670 940 1660 930 1610 860 1560 770 1550 760 1460 640 1450 620 1420 600 7/8 2530 1460 2320 1190 2220 1050 2200 1010 2140 920 2070 840 2050 820 1940 700 1920 680 1890 640 1 3260 1660 2980 1270 2860 1130 2840 1080 2750 1010 2670 920 2640 890 2490 750 2450 730 2360 710 5/8 1370 860 1260 760 1210 710 1200 700 1160 670 1130 640 1120 630 1060 580 1050 570 1030 560 5-1/2 1/4 3/4 1900 1140 1740 1000 1670 940 1660 930 1610 890 1560 810 1550 790 1460 660 1450 640 1420 620 7/8 2530 1460 2320 1240 2220 1090 2200 1050 2140 960 2070 880 2050 860 1940 730 1920 710 1890 660 1 3260 1730 2980 1320 2860 1170 2840 1130 2750 1050 2670 950 2640 930 2490 780 2470 760 2420 740 5/8 1370 860 1260 760 1210 710 1200 700 1160 670 1130 640 1120 630 1060 580 1050 570 1030 560 7-1/2 1/4 3/4 1900 1140 1740 1000 1670 940 1660 930 1610 890 1560 850 1550 840 1460 760 1450 750 1420 740 7/8 2530 1460 2320 1280 2220 1210 2200 1180 2140 1130 2070 1080 2050 1070 1940 960 1920 930 1890 870 1 3260 1820 2980 1590 2860 1500 2840 1470 2750 1400 2670 1270 2640 1230 2490 1030 2470 1000 2420 960 3/4 1900 1140 1740 1000 1670 940 1660 930 1610 890 1560 850 1550 840 1460 760 1450 750 1420 740 9-1/2 1/4 7/8 2530 1460 2320 1280 2220 1210 2200 1180 2140 1130 2070 1080 2050 1070 1940 980 1920 970 1890 930 1 3260 1820 2980 1590 2860 1500 2840 1470 2750 1420 2670 1350 2640 1330 2490 1220 2470 1200 2420 1180 11-1/2 1/4 7/8 2530 1460 2320 1280 2220 1210 2200 1180 2140 1130 2070 1080 2050 1070 1940 980 1920 970 1890 930 1 3260 1820 2980 1590 2860 1500 2840 1470 2750 1420 2670 1350 2640 1330 2490 1220 2470 1200 2420 1180 13-1/2 1/4 1 3260 1820 2980 1590 2860 1500 2840 1470 2750 1420 2670 1350 2640 1330 2490 1220 2470 1200 2420 1180 1. Tabulated lateral design values, Z, for bolted connections shall be multiplied by all applicable adjustment factors (see Table 11.3.1). 2. Tabulated lateral design values, Z, are for full-body diameter bolts (see Appendix Table L1) with bolt bending yield strength, F yb, of 45,000 psi and dowel bearing strength, F e, of 87,000 psi for ASTM A36 steel.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 95 Table 12C BOLTS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections 1,2 for structural glued laminated timber main member with sawn lumber side member of identical specific gravity Thickness G=0.36 Spruce-Pine-Fir(S) Western Woods G=0.42 Spruce-Pine-Fir G=0.43 Hem-Fir G=0.46 Douglas Fir(S) G=0.50 Douglas Fir-Larch G=0.55 Southern Pine Bolt Diameter Side Member Main Member t m t s D Z ll Z s Z m Z Z ll Z s Z m Z Z ll Z s Z m Z Z ll Z s Z m Z Z ll Z s Z m Z Z ll Z s Z m Z in. in. in. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. 1/2 - - - - 610 370 370 310 580 340 330 270 550 320 310 250 540 320 300 240 490 280 240 190 5/8 - - - - 850 520 430 340 780 470 390 300 730 420 360 270 710 410 350 270 610 330 290 210 2-1/2 1-1/2 3/4 - - - - 1020 590 500 380 940 520 450 330 870 460 410 300 850 450 400 290 740 360 330 230 7/8 - - - - 1190 630 550 410 1090 550 500 360 1020 500 450 320 1000 490 440 310 860 390 370 250 1 - - - - 1360 680 610 440 1250 600 550 390 1160 540 500 350 1140 530 490 340 980 420 410 270 1/2 660 400 470 360 - - - - - - - - - - - - - - - - - - - - 5/8 940 560 550 460 - - - - - - - - - - - - - - - - - - - - 3 1-1/2 3/4 1270 660 620 500 - - - - - - - - - - - - - - - - - - - - 7/8 1520 720 690 540 - - - - - - - - - - - - - - - - - - - - 1 1740 770 750 580 - - - - - - - - - - - - - - - - - - - - 1/2 - - - - 610 370 430 330 580 340 390 310 550 320 360 290 540 320 340 280 490 280 280 230 5/8 - - - - 880 520 500 410 830 470 450 370 790 420 410 330 780 410 400 320 710 330 330 260 3/4 - - - - 1200 590 570 460 1130 520 510 410 1060 460 460 360 1040 450 450 350 890 360 370 280 7/8 - - - - 1440 630 630 490 1320 550 560 430 1230 500 510 390 1210 490 500 380 1040 390 410 310 1 - - - - 1640 680 690 530 1510 600 620 470 1410 540 560 420 1380 530 550 410 1190 420 450 330 5/8 940 560 640 500 - - - - - - - - - - - - - - - - - - - - 3/4 1270 660 850 660 - - - - - - - - - - - - - - - - - - - - 7/8 1680 720 1020 720 - - - - - - - - - - - - - - - - - - - - 1-1/2 3-1/8 1-1/2 5 1 2150 770 1100 770 - - - - - - - - - - - - - - - - - - - - 5/8 - - - - 880 520 590 460 830 470 560 430 790 420 530 410 780 410 520 400 710 330 460 330 3/4 - - - - 1200 590 790 590 1140 520 740 520 1100 460 670 460 1080 450 660 450 990 360 530 360 7/8 - - - - 1590 630 920 630 1520 550 810 550 1460 500 740 500 1440 490 720 490 1330 390 590 390 1 - - - - 2050 680 990 680 1930 600 890 600 1800 540 810 540 1760 530 780 530 1520 420 640 420 5/8 940 560 640 500 880 520 590 460 830 470 560 430 790 420 530 410 780 410 520 400 710 330 460 330 3/4 1270 660 850 660 1200 590 790 590 1140 520 740 520 1100 460 700 460 1080 450 690 450 990 360 620 360 7/8 1680 720 1090 720 1590 630 1010 630 1520 550 950 550 1460 500 900 500 1440 490 890 490 1330 390 750 390 1 2150 770 1350 770 2050 680 1270 680 1930 600 1140 600 1800 540 1030 540 1760 530 1000 530 1520 420 810 420 1-1/2 5-1/8 1-1/2 6-3/4 1. Tabulated lateral design values, Z, for bolted connections shall be multiplied by all applicable adjustment factors (see Table 11.3.1). 2. Tabulated lateral design values, Z, are for full-body diameter bolts (see Appendix Table L1) with bolt bending yield strength, F yb, of 45,000 psi. BOLTS DOWEL-TYPE FASTENERS 12

96 DOWEL-TYPE FASTENERS BOLTS Table 12D Thickness Main Member Side Member BOLTS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections 1,2 for structural glued laminated timber main member with 1/4" ASTM A 36 steel side plate Bolt Diameter G=0.55 Southern Pine G=0.50 Douglas Fir-Larch G=0.46 Douglas Fir(S) Hem-Fir(N) G=0.43 Hem-Fir G=0.42 Spruce-Pine-Fir G=0.36 Spruce-Pine-Fir(S) Western Woods t m t s D Z ll Z Z ll Z Z ll Z Z ll Z Z ll Z Z ll Z in. in. in. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. 1/2 - - 830 410 780 380 740 350 720 340 640 290 5/8 - - 1050 470 980 430 920 400 910 390 800 330 2-1/2 1/4 3/4 - - 1270 530 1180 490 1110 450 1090 440 960 370 7/8 - - 1480 590 1370 530 1290 490 1270 480 1120 410 1 - - 1690 640 1570 580 1480 540 1450 530 1280 450 1/2 860 540 - - - - - - - - - - 5/8 1260 610 - - - - - - - - - - 3 1/4 3/4 1610 670 - - - - - - - - - - 7/8 1880 740 - - - - - - - - - - 1 2150 790 - - - - - - - - - - 1/2 - - 830 490 800 440 770 410 770 400 720 330 5/8 - - 1210 550 1160 500 1110 460 1090 450 960 380 3-1/8 1/4 3/4 - - 1540 620 1420 560 1340 510 1310 500 1150 420 7/8 - - 1790 680 1660 610 1560 560 1530 550 1340 470 1 - - 2050 740 1900 670 1780 610 1750 600 1530 510 5/8 1260 760 - - - - - - - - - - 5 1/4 3/4 1740 1000 - - - - - - - - - - 7/8 2320 1140 - - - - - - - - - - 1 2980 1210 - - - - - - - - - - 5/8 - - 1210 710 1160 670 1130 640 1120 630 1050 550 5-1/8 1/4 3/4 - - 1670 940 1610 840 1560 760 1550 740 1450 610 7/8 - - 2220 1020 2140 900 2070 830 2050 810 1920 670 1 - - 2860 1100 2750 990 2670 900 2640 880 2390 720 5/8 1260 760 1210 710 1160 670 1130 640 1120 630 1050 570 6-3/4 1/4 3/4 1740 1000 1670 940 1610 890 1560 850 1550 840 1450 750 7/8 2320 1280 2220 1210 2140 1130 2070 1060 2050 1030 1920 850 1 2980 1590 2860 1420 2750 1270 2670 1150 2640 1120 2470 910 3/4 1740 1000 - - - - - - - - - - 8-1/2 1/4 7/8 2320 1280 - - - - - - - - - - 1 2980 1590 - - - - - - - - - - 3/4 - - 1670 940 1610 890 1560 850 1550 840 1450 750 8-3/4 1/4 7/8 - - 2220 1210 2140 1130 2070 1080 2050 1070 1920 970 1 - - 2860 1500 2750 1420 2670 1350 2640 1330 2470 1150 10-1/2 10-3/4 12-1/4 1/4 1/4 1/4 7/8 7/8 7/8 2320 - - 1280 - - - 2220 2220-1210 1210-2140 2140-1130 1130-2070 2070-1080 1080-2050 2050-1070 1070-1920 1920-970 970 1 1 1 2980 - - 1590 - - - 2860 2860-1500 1500-2750 2750-1420 1420-2670 2670-1350 1350-2640 2640-1330 1330-2470 2470-1200 1200 14-1/4 1/4 1 - - 2860 1500 2750 1420 2670 1350 2640 1330 2470 1200 1. Tabulated lateral design values, Z, for bolted connections shall be multiplied by all applicable adjustment factors (see Table 11.3.1). 2. Tabulated lateral design values, Z, are for full-body diameter bolts (see Appendix Table L1) with bolt bending yield strength, F yb, of 45,000 psi and dowel bearing strength, F e, of 87,000 psi for ASTM A36 steel.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 97 Table 12E BOLTS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections 1,2,3,4 for sawn lumber or SCL to concrete Thickness Embedment Depth in Concrete Side Member Bolt Diameter G=0.67 Red Oak G=0.55 Mixed Maple Southern Pine G=0.50 Douglas Fir-Larch G=0.49 Douglas Fir-Larch(N) G=0.46 Douglas Fir(S) Hem-Fir(N) BOLTS t m t s D Z ll Z Z ll Z Z ll Z Z ll Z Z ll Z in. in. in. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. 1/2 770 480 680 410 650 380 640 380 620 360 6.0 and greater Embedment Depth in Concrete 1-3/4 Thickness Side Member 5/8 1070 660 970 580 930 530 920 520 890 470 3/4 1450 890 1330 660 1270 590 1260 560 1230 520 7/8 1890 960 1750 720 1690 630 1680 600 1640 550 1 2410 1020 2250 770 2100 680 2060 650 1930 600 1/2 830 510 740 430 700 400 690 390 670 370 5/8 1160 680 1030 600 980 550 970 550 940 530 3/4 1530 900 1390 770 1330 680 1310 660 1270 600 7/8 1970 1120 1800 840 1730 740 1720 700 1680 640 1 2480 1190 2290 890 2210 790 2200 750 2150 700 1/2 830 590 790 520 770 470 760 460 750 440 5/8 1290 800 1230 670 1180 610 1170 610 1120 570 3/4 1840 1000 1630 850 1540 800 1520 780 1460 750 7/8 2290 1240 2050 1080 1940 1020 1920 1000 1860 920 1 2800 1520 2530 1280 2410 1130 2390 1080 2310 1000 1/2 830 590 790 540 770 510 760 500 750 490 5/8 1290 880 1230 810 1200 730 1190 720 1170 670 3/4 1860 1190 1770 980 1720 900 1720 880 1680 830 7/8 2540 1410 2410 1190 2320 1100 2290 1070 2200 1020 1 3310 1670 2970 1420 2800 1330 2770 1300 2660 1260 t m t s D Z ll Z Z ll Z Z ll Z Z ll Z Z ll Z in. in. in. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. 1/2 590 340 590 340 550 310 540 290 530 290 6.0 and greater 1-1/2 2-1/2 3-1/2 1-1/2 1-3/4 2-1/2 3-1/2 Bolt Diameter G=0.43 Hem-Fir G=0.42 Spruce-Pine-Fir G=0.37 Redwood (open grain) G=0.36 Eastern Softwoods Spruce-Pine-Fir(S) Western Cedars Western Woods G=0.35 Northern Species 5/8 860 420 850 410 810 350 800 330 780 320 3/4 1200 460 1190 450 1130 370 1120 360 1100 350 7/8 1580 500 1540 490 1360 410 1330 390 1280 370 1 1800 540 1760 530 1560 440 1520 420 1460 410 1/2 640 360 630 350 580 320 580 310 560 310 5/8 910 490 900 480 840 400 830 380 810 370 3/4 1230 540 1220 530 1160 430 1140 420 1120 410 7/8 1630 580 1610 570 1540 470 1520 460 1490 430 1 2090 630 2060 610 1820 510 1770 490 1710 470 1/2 730 410 730 400 700 360 690 340 680 340 5/8 1070 540 1060 530 980 480 960 470 940 460 3/4 1400 710 1380 700 1290 620 1270 600 1240 580 7/8 1790 830 1770 810 1660 680 1640 660 1600 610 1 2230 900 2210 880 2080 730 2060 700 2030 680 1/2 730 470 730 470 700 430 690 410 690 400 5/8 1140 620 1140 610 1090 550 1080 530 1070 520 3/4 1650 780 1640 770 1540 680 1510 670 1470 660 7/8 2100 960 2070 950 1910 870 1880 850 1840 820 1 2550 1190 2520 1180 2340 1020 2310 980 2260 950 DOWEL-TYPE FASTENERS 12 1. Tabulated lateral design values, Z, for bolted connections shall be multiplied by all applicable adjustment factors (see Table 11.3.1). 2. Tabulated lateral design values, Z, are for full-body diameter bolts (see Appendix Table L1) with bolt bending yield strength, F yb, of 45,000 psi. 3. Tabulated lateral design values, Z, are based on dowel bearing strength, F e, of 7,500 psi for concrete with minimum f c '=2,500 psi. 4. Six inch anchor embedment assumed.

98 DOWEL-TYPE FASTENERS BOLTS Table 12F Thickness Main Member BOLTS: Reference Lateral Design Values, Z, for Double Shear (three member) Connections 1,2 for sawn lumber or SCL with all members of identical specific gravity Side Member Bolt Diameter G=0.67 Red Oak G=0.55 Mixed Maple Southern Pine G=0.50 Douglas Fir-Larch G=0.49 Douglas Fir-Larch(N) G=0.46 Douglas Fir(S) Hem-Fir(N) t m t s D Z ll Z s Z m Z ll Z s Z m Z ll Z s Z m Z ll Z s Z m Z ll Z s Z m in. in. in. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. 1/2 1410 960 730 1150 800 550 1050 730 470 1030 720 460 970 680 420 5/8 1760 1310 810 1440 1130 610 1310 1040 530 1290 1030 520 1210 940 470 1-1/2 1-1/2 3/4 2110 1690 890 1730 1330 660 1580 1170 590 1550 1130 560 1450 1040 520 7/8 2460 1920 960 2020 1440 720 1840 1260 630 1800 1210 600 1690 1100 550 1 2810 2040 1020 2310 1530 770 2100 1350 680 2060 1290 650 1930 1200 600 1/2 1640 1030 850 1350 850 640 1230 770 550 1200 750 530 1130 710 490 5/8 2050 1370 940 1680 1160 710 1530 1070 610 1500 1060 600 1410 1000 550 1-3/4 1-3/4 3/4 2460 1810 1040 2020 1550 770 1840 1370 680 1800 1310 660 1690 1210 600 7/8 2870 2240 1120 2350 1680 840 2140 1470 740 2110 1410 700 1970 1290 640 1 3280 2380 1190 2690 1790 890 2450 1580 790 2410 1510 750 2250 1400 700 1/2 1530 960 1120 1320 800 910 1230 730 790 1210 720 760 1160 680 700 5/8 2150 1310 1340 1870 1130 1020 1760 1040 880 1740 1030 860 1660 940 780 2-1/2 1-1/2 3/4 2890 1770 1480 2550 1330 1110 2400 1170 980 2380 1130 940 2280 1040 860 7/8 3780 1920 1600 3360 1440 1200 3060 1260 1050 3010 1210 1010 2820 1100 920 1 4690 2040 1700 3840 1530 1280 3500 1350 1130 3440 1290 1080 3220 1200 1000 1/2 1530 960 1120 1320 800 940 1230 730 860 1210 720 850 1160 680 810 5/8 2150 1310 1510 1870 1130 1290 1760 1040 1190 1740 1030 1170 1660 940 1090 1-1/2 3/4 2890 1770 1980 2550 1330 1550 2400 1170 1370 2380 1130 1310 2280 1040 1210 7/8 3780 1920 2240 3360 1440 1680 3180 1260 1470 3150 1210 1410 3030 1100 1290 1 4820 2040 2380 4310 1530 1790 4090 1350 1580 4050 1290 1510 3860 1200 1400 1/2 1660 1030 1180 1430 850 1030 1330 770 940 1310 750 920 1250 710 870 5/8 2310 1370 1630 1990 1160 1380 1860 1070 1230 1840 1060 1200 1760 1000 1090 3-1/2 1-3/4 3/4 3060 1810 2070 2670 1550 1550 2510 1370 1370 2480 1310 1310 2370 1210 1210 7/8 3940 2240 2240 3470 1680 1680 3270 1470 1470 3240 1410 1410 3110 1290 1290 1 4960 2380 2380 4400 1790 1790 4170 1580 1580 4120 1510 1510 3970 1400 1400 1/2 1660 1180 1180 1500 1040 1040 1430 970 970 1420 960 960 1370 920 920 5/8 2590 1770 1770 2340 1560 1420 2240 1410 1230 2220 1390 1200 2150 1290 1090 3-1/2 3/4 3730 2380 2070 3380 1910 1550 3220 1750 1370 3190 1700 1310 3090 1610 1210 7/8 5080 2820 2240 4600 2330 1680 4290 2130 1470 4210 2070 1410 3940 1960 1290 1 6560 3340 2380 5380 2780 1790 4900 2580 1580 4810 2520 1510 4510 2410 1400 5/8 2150 1310 1510 1870 1130 1290 1760 1040 1190 1740 1030 1170 1660 940 1110 1-1/2 3/4 2890 1770 1980 2550 1330 1690 2400 1170 1580 2380 1130 1550 2280 1040 1480 7/8 3780 1920 2520 3360 1440 2170 3180 1260 2030 3150 1210 1990 3030 1100 1900 1 4820 2040 3120 4310 1530 2680 4090 1350 2360 4050 1290 2260 3860 1200 2100 5/8 2310 1370 1630 1990 1160 1380 1860 1070 1270 1840 1060 1250 1760 1000 1180 5-1/4 1-3/4 3/4 3060 1810 2110 2670 1550 1790 2510 1370 1660 2480 1310 1630 2370 1210 1550 7/8 3940 2240 2640 3470 1680 2260 3270 1470 2100 3240 1410 2060 3110 1290 1930 1 4960 2380 3240 4400 1790 2680 4170 1580 2360 4120 1510 2260 3970 1400 2100 5/8 2590 1770 1770 2340 1560 1560 2240 1410 1460 2220 1390 1450 2150 1290 1390 3-1/2 3/4 3730 2380 2480 3380 1910 2180 3220 1750 2050 3190 1700 1970 3090 1610 1810 7/8 5080 2820 3290 4600 2330 2530 4390 2130 2210 4350 2070 2110 4130 1960 1930 1 6630 3340 3570 5740 2780 2680 5330 2580 2360 5250 2520 2260 4990 2410 2100 5/8 2150 1310 1510 1870 1130 1290 1760 1040 1190 1740 1030 1170 1660 940 1110 1-1/2 3/4 2890 1770 1980 2550 1330 1690 2400 1170 1580 2380 1130 1550 2280 1040 1480 7/8 3780 1920 2520 3360 1440 2170 3180 1260 2030 3150 1210 1990 3030 1100 1900 5-1/2 1 4820 2040 3120 4310 1530 2700 4090 1350 2480 4050 1290 2370 3860 1200 2200 5/8 2590 1770 1770 2340 1560 1560 2240 1410 1460 2220 1390 1450 2150 1290 1390 3-1/2 3/4 3730 2380 2480 3380 1910 2180 3220 1750 2050 3190 1700 2020 3090 1610 1900 7/8 5080 2820 3290 4600 2330 2650 4390 2130 2310 4350 2070 2210 4130 1960 2020 1 6630 3340 3740 5740 2780 2810 5330 2580 2480 5250 2520 2370 4990 2410 2200 5/8 2150 1310 1510 1870 1130 1290 1760 1040 1190 1740 1030 1170 1660 940 1110 1-1/2 3/4 2890 1770 1980 2550 1330 1690 2400 1170 1580 2380 1130 1550 2280 1040 1480 7/8 3780 1920 2520 3360 1440 2170 3180 1260 2030 3150 1210 1990 3030 1100 1900 7-1/2 1 4820 2040 3120 4310 1530 2700 4090 1350 2530 4050 1290 2480 3860 1200 2390 5/8 2590 1770 1770 2340 1560 1560 2240 1410 1460 2220 1390 1450 2150 1290 1390 3-1/2 3/4 3730 2380 2480 3380 1910 2180 3220 1750 2050 3190 1700 2020 3090 1610 1940 7/8 5080 2820 3290 4600 2330 2890 4390 2130 2720 4350 2070 2670 4130 1960 2560 1 6630 3340 4190 5740 2780 3680 5330 2580 3380 5250 2520 3230 4990 2410 3000 1. Tabulated lateral design values, Z, for bolted connections shall be multiplied by all applicable adjustment factors (see Table 11.3.1). 2. Tabulated lateral design values, Z, are for full-body diameter bolts (see Appendix Table L1) with bolt bending yield strength, F yb, of 45,000 psi.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 99 Table 12F (Cont.) Thickness Main Member BOLTS: Reference Lateral Design Values, Z, for Double Shear (three member) Connections 1,2 for sawn lumber or SCL with all members of identical specific gravity Side Member Bolt Diameter G=0.43 Hem-Fir G=0.42 Spruce-Pine-Fir G=0.37 Redwood (open grain) G=0.36 Eastern Softwoods Spruce-Pine-Fir(S) Western Cedars Western Woods G=0.35 Northern Species BOLTS t m t s D Z ll Z s Z m Z ll Z s Z m Z ll Z s Z m Z ll Z s Z m Z ll Z s Z m in. in. in. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. 1/2 900 650 380 880 640 370 780 580 310 760 560 290 730 550 290 5/8 1130 840 420 1100 830 410 970 690 350 950 660 330 910 640 320 1-1/2 1-1/2 3/4 1350 920 460 1320 900 450 1170 740 370 1140 720 360 1100 700 350 7/8 1580 1000 500 1540 970 490 1360 810 410 1330 790 390 1280 740 370 1 1800 1080 540 1760 1050 530 1560 870 440 1520 840 420 1460 810 410 1/2 1050 670 450 1030 660 430 910 590 360 890 580 340 850 570 330 5/8 1310 950 490 1290 940 480 1130 810 400 1110 770 380 1070 740 370 1-3/4 1-3/4 3/4 1580 1080 540 1540 1050 530 1360 870 430 1330 840 420 1280 810 410 7/8 1840 1160 580 1800 1130 570 1590 950 470 1550 920 460 1490 860 430 1 2100 1260 630 2060 1230 610 1820 1020 510 1770 980 490 1710 950 470 1/2 1100 650 640 1080 640 610 990 580 510 980 560 490 950 550 480 5/8 1590 840 700 1570 830 690 1450 690 580 1430 660 550 1390 640 530 2-1/2 1-1/2 3/4 2190 920 770 2160 900 750 1950 740 620 1900 720 600 1830 700 580 7/8 2630 1000 830 2570 970 810 2270 810 680 2210 790 660 2130 740 610 1 3000 1080 900 2940 1050 880 2590 870 730 2530 840 700 2440 810 680 1/2 1100 650 760 1080 640 740 990 580 670 980 560 660 950 550 640 5/8 1590 840 980 1570 830 960 1450 690 810 1430 660 770 1390 640 740 1-1/2 3/4 2190 920 1080 2160 900 1050 2010 740 870 1990 720 840 1940 700 810 7/8 2920 1000 1160 2880 970 1130 2690 810 950 2660 790 920 2560 740 860 1 3600 1080 1260 3530 1050 1230 3110 870 1020 3040 840 980 2930 810 950 1/2 1180 670 820 1160 660 800 1060 590 720 1040 580 680 1010 570 670 5/8 1670 950 980 1650 940 960 1510 810 810 1490 770 770 1450 740 740 3-1/2 1-3/4 3/4 2270 1080 1080 2240 1050 1050 2070 870 870 2040 840 840 1990 810 810 7/8 2980 1160 1160 2950 1130 1130 2740 950 950 2700 920 920 2640 860 860 1 3820 1260 1260 3770 1230 1230 3520 1020 1020 3480 980 980 3410 950 950 1/2 1330 880 880 1310 870 860 1230 800 720 1220 780 680 1200 760 670 5/8 2070 1190 980 2050 1170 960 1930 1030 810 1900 1000 770 1870 970 740 3-1/2 3/4 2980 1490 1080 2950 1460 1050 2720 1290 870 2660 1270 840 2560 1240 810 7/8 3680 1840 1160 3600 1810 1130 3180 1640 950 3100 1610 920 2990 1550 860 1 4200 2280 1260 4110 2240 1230 3630 2030 1020 3540 1960 980 3410 1890 950 5/8 1590 840 1050 1570 830 1040 1450 690 940 1430 660 920 1390 640 900 1-1/2 3/4 2190 920 1400 2160 900 1380 2010 740 1250 1990 720 1230 1940 700 1210 7/8 2920 1000 1750 2880 970 1700 2690 810 1420 2660 790 1380 2560 740 1290 1 3600 1080 1890 3530 1050 1840 3110 870 1520 3040 840 1470 2930 810 1420 5/8 1670 950 1110 1650 940 1100 1510 810 990 1490 770 970 1450 740 940 5-1/4 1-3/4 3/4 2270 1080 1460 2240 1050 1440 2070 870 1300 2040 840 1260 1990 810 1220 7/8 2980 1160 1750 2950 1130 1700 2740 950 1420 2700 920 1380 2640 860 1290 1 3820 1260 1890 3770 1230 1840 3520 1020 1520 3480 980 1470 3410 950 1420 5/8 2070 1190 1320 2050 1170 1310 1930 1030 1210 1900 1000 1150 1870 970 1120 3-1/2 3/4 2980 1490 1610 2950 1460 1580 2770 1290 1300 2740 1270 1260 2660 1240 1220 7/8 3900 1840 1750 3840 1810 1700 3480 1640 1420 3410 1610 1380 3320 1550 1290 1 4730 2280 1890 4660 2240 1840 4240 2030 1520 4170 1960 1470 4050 1890 1420 5/8 1590 840 1050 1570 830 1040 1450 690 940 1430 660 920 1390 640 900 1-1/2 3/4 2190 920 1400 2160 900 1380 2010 740 1250 1990 720 1230 1940 700 1210 7/8 2920 1000 1800 2880 970 1780 2690 810 1490 2660 790 1440 2560 740 1350 5-1/2 1 3600 1080 1980 3530 1050 1930 3110 870 1600 3040 840 1540 2930 810 1490 5/8 2070 1190 1320 2050 1170 1310 1930 1030 1210 1900 1000 1180 1870 970 1160 3-1/2 3/4 2980 1490 1690 2950 1460 1650 2770 1290 1360 2740 1270 1320 2660 1240 1280 7/8 3900 1840 1830 3840 1810 1780 3480 1640 1490 3410 1610 1440 3320 1550 1350 1 4730 2280 1980 4660 2240 1930 4240 2030 1600 4170 1960 1540 4050 1890 1490 5/8 1590 840 1050 1570 830 1040 1450 690 940 1430 660 920 1390 640 900 1-1/2 3/4 2190 920 1400 2160 900 1380 2010 740 1250 1990 720 1230 1940 700 1210 7/8 2920 1000 1800 2880 970 1780 2690 810 1630 2660 790 1600 2560 740 1550 7-1/2 1 3600 1080 2270 3530 1050 2240 3110 870 2040 3040 840 2010 2930 810 1970 5/8 2070 1190 1320 2050 1170 1310 1930 1030 1210 1900 1000 1180 1870 970 1160 3-1/2 3/4 2980 1490 1850 2950 1460 1820 2770 1290 1670 2740 1270 1650 2660 1240 1620 7/8 3900 1840 2450 3840 1810 2420 3480 1640 2030 3410 1610 1970 3320 1550 1840 1 4730 2280 2700 4660 2240 2630 4240 2030 2180 4170 1960 2100 4050 1890 2030 1. Tabulated lateral design values, Z, for bolted connections shall be multiplied by all applicable adjustment factors (see Table 11.3.1). 2. Tabulated lateral design values, Z, are for full-body diameter bolts (see Appendix Table L1) with bolt bending yield strength, F yb, of 45,000 psi. DOWEL-TYPE FASTENERS 12

100 DOWEL-TYPE FASTENERS BOLTS Table 12G Thickness Main Member Side Member Bolt Diameter BOLTS: Reference Lateral Design Values, Z, for Double Shear (three member) Connections 1,2 for sawn lumber or SCL main member with 1/4" ASTM A 36 steel side plates G=0.67 Red Oak G=0.55 Mixed Maple Southern Pine G=0.50 Douglas Fir-Larch G=0.49 Douglas Fir-Larch (N) G=0.46 Douglas Fir(S) Hem-Fir(N) G=0.43 Hem-Fir G=0.42 Spruce-Pine-Fir G=0.37 Redwood (open grain) G=0.36 Eastern Softwoods Spruce-Pine-Fir(S) Western Cedars Western Woods G=0.35 Northern Species t m t s D Z ll Z Z ll Z Z ll Z Z ll Z Z ll Z Z ll Z Z ll Z Z ll Z Z ll Z Z ll Z in. in. in. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. 1/2 1410 730 1150 550 1050 470 1030 460 970 420 900 380 880 370 780 310 760 290 730 290 5/8 1760 810 1440 610 1310 530 1290 520 1210 470 1130 420 1100 410 970 350 950 330 910 320 1-1/2 1/4 3/4 2110 890 1730 660 1580 590 1550 560 1450 520 1350 460 1320 450 1170 370 1140 360 1100 350 7/8 2460 960 2020 720 1840 630 1800 600 1690 550 1580 500 1540 490 1360 410 1330 390 1280 370 1 2810 1020 2310 770 2100 680 2060 650 1930 600 1800 540 1760 530 1560 440 1520 420 1460 410 1/2 1640 850 1350 640 1230 550 1200 530 1130 490 1050 450 1030 430 910 360 890 340 850 330 5/8 2050 940 1680 710 1530 610 1500 600 1410 550 1310 490 1290 480 1130 400 1110 380 1070 370 1-3/4 1/4 3/4 2460 1040 2020 770 1840 680 1800 660 1690 600 1580 540 1540 530 1360 430 1330 420 1280 410 7/8 2870 1120 2350 840 2140 740 2110 700 1970 640 1840 580 1800 570 1590 470 1550 460 1490 430 1 3280 1190 2690 890 2450 790 2410 750 2250 700 2100 630 2060 610 1820 510 1770 490 1710 470 1/2 1870 1210 1720 910 1650 790 1640 760 1590 700 1500 640 1470 610 1300 510 1270 490 1220 480 5/8 2740 1340 2400 1020 2190 880 2150 860 2010 780 1880 700 1840 690 1620 580 1580 550 1520 530 2-1/2 1/4 3/4 3520 1480 2880 1110 2630 980 2580 940 2410 860 2250 770 2200 750 1950 620 1900 600 1830 580 7/8 4100 1600 3360 1200 3060 1050 3010 1010 2820 920 2630 830 2570 810 2270 680 2210 660 2130 610 1 4690 1700 3840 1280 3500 1130 3440 1080 3220 1000 3000 900 2940 880 2590 730 2530 700 2440 680 1/2 1870 1240 1720 1100 1650 1030 1640 1010 1590 970 1540 890 1530 860 1450 720 1430 680 1410 670 5/8 2740 1720 2510 1420 2410 1230 2390 1200 2330 1090 2260 980 2230 960 2110 810 2090 770 2060 740 3-1/2 1/4 3/4 3800 2070 3480 1550 3340 1370 3320 1310 3220 1210 3120 1080 3080 1050 2720 870 2660 840 2560 810 7/8 5060 2240 4630 1680 4290 1470 4210 1410 3940 1290 3680 1160 3600 1130 3180 950 3100 920 2990 860 1 6520 2380 5380 1790 4900 1580 4810 1510 4510 1400 4200 1260 4110 1230 3630 1020 3540 980 3410 950 5/8 2740 1720 2510 1510 2410 1420 2390 1400 2330 1340 2260 1280 2230 1270 2110 1170 2090 1140 2060 1120 3/4 3800 2290 3480 2000 3340 1890 3320 1850 3220 1780 3120 1610 3090 1580 2920 1300 2890 1260 2840 1220 5-1/4 1/4 7/8 5060 2930 4630 2530 4440 2210 4410 2110 4280 1930 4150 1750 4110 1700 3880 1420 3840 1380 3770 1290 1 6520 3570 5960 2680 5720 2360 5670 2260 5510 2100 5330 1890 5280 1840 4990 1520 4930 1470 4850 1420 5/8 2740 1720 2510 1510 2410 1420 2390 1400 2330 1340 2260 1280 2230 1270 2110 1170 2090 1140 2060 1120 3/4 3800 2290 3480 2000 3340 1890 3320 1850 3220 1780 3120 1690 3090 1650 2920 1360 2890 1320 2840 1280 5-1/2 1/4 7/8 5060 2930 4630 2570 4440 2310 4410 2210 4280 2020 4150 1830 4110 1780 3880 1490 3840 1440 3770 1350 1 6520 3640 5960 2810 5720 2480 5670 2370 5510 2200 5330 1980 5280 1930 4990 1600 4930 1540 4850 1490 5/8 2740 1720 2510 1510 2410 1420 2390 1400 2330 1340 2260 1280 2230 1270 2110 1170 2090 1140 2060 1120 3/4 3800 2290 3480 2000 3340 1890 3320 1850 3220 1780 3120 1690 3090 1670 2920 1530 2890 1500 2840 1480 7-1/2 1/4 7/8 5060 2930 4630 2570 4440 2410 4410 2360 4280 2260 4150 2160 4110 2130 3880 1960 3840 1930 3770 1840 1 6520 3640 5960 3180 5720 3000 5670 2940 5510 2840 5330 2700 5280 2630 4990 2180 4930 2100 4850 2030 3/4 3800 2290 3480 2000 3340 1890 3320 1850 3220 1780 3120 1690 3090 1670 2920 1530 2890 1500 2840 1480 9-1/2 1/4 7/8 5060 2930 4630 2570 4440 2410 4410 2360 4280 2260 4150 2160 4110 2130 3880 1960 3840 1930 3770 1870 1 6520 3640 5960 3180 5720 3000 5670 2940 5510 2840 5330 2700 5280 2660 4990 2440 4930 2400 4850 2350 7/8 5060 2930 4630 2570 4440 2410 4410 2360 4280 2260 4150 2160 4110 2130 3880 1960 3840 1930 3770 1870 11-1/2 1/4 1 6520 3640 5960 3180 5720 3000 5670 2940 5510 2840 5330 2700 5280 2660 4990 2440 4930 2400 4850 2350 13-1/2 1/4 1 6520 3640 5960 3180 5720 3000 5670 2940 5510 2840 5330 2700 5280 2660 4990 2440 4930 2400 4850 2350 1. Tabulated lateral design values, Z, for bolted connections shall be multiplied by all applicable adjustment factors (see Table 11.3.1). 2. Tabulated lateral design values, Z, are for full-body diameter bolts (see Appendix Table L1) with bolt bending yield strength, F yb, of 45,000 psi and dowel bearing strength, F e, of 87,000 psi for ASTM A36 steel.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 101 Table 12H Thickness Main Member Side Member Bolt Diameter BOLTS: Reference Lateral Design Values, Z, for Double Shear (three member) Connections 1,2 for structural glued laminated timber main member with sawn lumber side members of identical specific gravity G=0.55 Southern Pine G=0.50 Douglas Fir- Larch G=0.46 Douglas Fir(S) Hem-Fir(N) G=0.43 Hem-Fir G=0.42 Spruce-Pine-Fir G=0.36 Spruce-Pine-Fir(S) Western Woods BOLTS t m t s D Z ll Z s Z m Z ll Z s Z m Z ll Z s Z m Z ll Z s Z m Z ll Z s Z m Z ll Z s Z m in. in. in. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. 1/2 - - - 1230 730 790 1160 680 700 1100 650 640 1080 640 610 980 560 490 5/8 - - - 1760 1040 880 1660 940 780 1590 840 700 1570 830 690 1430 660 550 2-1/2 1-1/2 3/4 - - - 2400 1170 980 2280 1040 860 2190 920 770 2160 900 750 1900 720 600 7/8 - - - 3060 1260 1050 2820 1100 920 2630 1000 830 2570 970 810 2210 790 660 1 - - - 3500 1350 1130 3220 1200 1000 3000 1080 900 2940 1050 880 2530 840 700 1/2 1320 800 940 - - - - - - - - - - - - - - - 5/8 1870 1130 1220 - - - - - - - - - - - - - - - 3 1-1/2 3/4 2550 1330 1330 - - - - - - - - - - - - - - - 7/8 3360 1440 1440 - - - - - - - - - - - - - - - 1 4310 1530 1530 - - - - - - - - - - - - - - - 1/2 - - - 1230 730 860 1160 680 810 1100 650 760 1080 640 740 980 560 610 5/8 - - - 1760 1040 1090 1660 940 980 1590 840 880 1570 830 860 1430 660 680 3-1/8 1-1/2 3/4 - - - 2400 1170 1220 2280 1040 1080 2190 920 960 2160 900 940 1990 720 750 7/8 - - - 3180 1260 1310 3030 1100 1150 2920 1000 1040 2880 970 1010 2660 790 820 1 - - - 4090 1350 1410 3860 1200 1250 3600 1080 1130 3530 1050 1090 3040 840 880 5/8 1870 1130 1290 - - - - - - - - - - - - - - - 5 1-1/2 3/4 2550 1330 1690 - - - - - - - - - - - - - - - 7/8 3360 1440 2170 - - - - - - - - - - - - - - - 1 4310 1530 2550 - - - - - - - - - - - - - - - 5/8 - - - 1760 1040 1190 1660 940 1110 1590 840 1050 1570 830 1040 1430 660 920 5-1/8 1-1/2 3/4 - - - 2400 1170 1580 2280 1040 1480 2190 920 1400 2160 900 1380 1990 720 1230 7/8 - - - 3180 1260 2030 3030 1100 1880 2920 1000 1700 2880 970 1660 2660 790 1350 1 - - - 4090 1350 2310 3860 1200 2050 3600 1080 1850 3530 1050 1790 3040 840 1440 5/8 1870 1130 1290 1760 1040 1190 1660 940 1110 1590 840 1050 1570 830 1040 1430 660 920 6-3/4 1-1/2 3/4 2550 1330 1690 2400 1170 1580 2280 1040 1480 2190 920 1400 2160 900 1380 1990 720 1230 7/8 3360 1440 2170 3180 1260 2030 3030 1100 1900 2920 1000 1800 2880 970 1780 2660 790 1600 1 4310 1530 2700 4090 1350 2530 3860 1200 2390 3600 1080 2270 3530 1050 2240 3040 840 1890 1. Tabulated lateral design values, Z, for bolted connections shall be multiplied by all applicable adjustment factors (see Table 11.3.1). 2. Tabulated lateral design values, Z, are for full-body diameter bolts (see Appendix Table L1) with bolt bending yield strength, F yb, of 45,000 psi. DOWEL-TYPE FASTENERS 12

102 DOWEL-TYPE FASTENERS BOLTS Table 12I Thickness BOLTS: Reference Lateral Design Values, Z, for Double Shear (three member) Connections 1,2 for structural glued laminated timber main member with 1/4" ASTM A 36 steel side plates Main Member Side Member Bolt Diameter G=0.55 Southern Pine G=0.50 Douglas Fir-Larch G=0.46 Douglas Fir(S) Hem-Fir(N) G=0.43 Hem-Fir G=0.42 Spruce-Pine-Fir G=0.36 Spruce-Pine-Fir(S) Western Woods t m t s D Z ll Z Z ll Z Z ll Z Z ll Z Z ll Z Z ll Z in. in. in. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. 1/2 - - 1650 790 1590 700 1500 640 1470 610 1270 490 5/8 - - 2190 880 2010 780 1880 700 1840 690 1580 550 2-1/2 1/4 3/4 - - 2630 980 2410 860 2250 770 2200 750 1900 600 7/8 - - 3060 1050 2820 920 2630 830 2570 810 2210 660 1 - - 3500 1130 3220 1000 3000 900 2940 880 2530 700 1/2 1720 1100 - - - - - - - - - - 5/8 2510 1220 - - - - - - - - - - 3 1/4 3/4 3460 1330 - - - - - - - - - - 7/8 4040 1440 - - - - - - - - - - 1 4610 1530 - - - - - - - - - - 1/2 - - 1650 980 1590 880 1540 800 1530 770 1430 610 5/8 - - 2410 1090 2330 980 2260 880 2230 860 1980 680 3-1/8 1/4 3/4 - - 3280 1220 3020 1080 2810 960 2750 940 2370 750 7/8 - - 3830 1310 3520 1150 3280 1040 3210 1010 2770 820 1 - - 4380 1410 4020 1250 3750 1130 3670 1090 3160 880 5/8 2510 1510 - - - - - - - - - - 5 1/4 3/4 3480 2000 - - - - - - - - - - 7/8 4630 2410 - - - - - - - - - - 1 5960 2550 - - - - - - - - - - 5/8 - - 2410 1420 2330 1340 2260 1280 2230 1270 2090 1120 5-1/8 1/4 3/4 - - 3340 1890 3220 1770 3120 1580 3090 1540 2890 1230 7/8 - - 4440 2150 4280 1880 4150 1700 4110 1660 3840 1350 1 - - 5720 2310 5510 2050 5330 1850 5280 1790 4930 1440 5/8 2510 1510 2410 1420 2330 1340 2260 1280 2230 1270 2090 1140 6-3/4 1/4 3/4 3480 2000 3340 1890 3220 1780 3120 1690 3090 1670 2890 1500 7/8 4630 2570 4440 2410 4280 2260 4150 2160 4110 2130 3840 1770 1 5960 3180 5720 3000 5510 2700 5330 2430 5280 2360 4930 1890 3/4 3480 2000 - - - - - - - - - - 8-1/2 1/4 7/8 4630 2570 - - - - - - - - - - 1 5960 3180 - - - - - - - - - - 3/4 - - 3340 1890 3220 1780 3120 1690 3090 1670 2890 1500 8-3/4 1/4 7/8 - - 4440 2410 4280 2260 4150 2160 4110 2130 3840 1930 1 - - 5720 3000 5510 2840 5330 2700 5280 2660 4930 2400 10-1/2 10-3/4 12-1/4 1/4 1/4 1/4 7/8 7/8 7/8 4630 - - 2570 - - - 4440 4440-2410 2410-4280 4280-2260 2260-4150 4150-2160 2160-4110 4110-2130 2130-3840 3840-1930 1930 1 1 1 5960 - - 3180 - - - 5720 5720-3000 3000-5510 5510-2840 2840-5330 5330-2700 2700-5280 5280-2660 2660-4930 4930-2400 2400 14-1/4 1/4 1 - - 5720 3000 5510 2840 5330 2700 5280 2660 4930 2400 1. Tabulated lateral design values, Z, for bolted connections shall be multiplied by all applicable adjustment factors (see Table 11.3.1). 2. Tabulated lateral design values, Z, are for full-body diameter bolts (see Appendix Table L1) with bolt bending yield strength, F yb, of 45,000 psi and dowel bearing strength, F e, of 87,000 psi for ASTM A36 steel.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 103 BOLTS This page left blank intentionally. DOWEL-TYPE FASTENERS 12

104 DOWEL-TYPE FASTENERS LAG SCREWS Table 12J Side Member Thickness Lag Screw Diameter LAG SCREWS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections 1,2,3,4 for sawn lumber or SCL with both members of identical specific gravity (tabulated lateral design values are calculated based on an assumed length of lag screw penetration, p, into the main member equal to 8D) G=0.67 Red Oak G=0.55 Mixed Maple Southern Pine G=0.50 Douglas Fir-Larch G=0.49 Douglas Fir-Larch(N) G=0.46 Douglas Fir(S) Hem-Fir(N) t s D Z ll Z s Z m Z Z ll Z s Z m Z Z ll Z s Z m Z Z ll Z s Z m Z Z ll Z s Z m Z in. in. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. 1/2 1/4 150 110 110 110 130 90 100 90 120 90 90 80 120 90 90 80 110 80 90 80 5/16 170 130 130 120 150 110 120 100 150 100 110 100 140 100 110 90 140 100 100 90 3/8 180 130 130 120 160 110 110 100 150 100 110 90 150 90 110 90 140 90 100 90 5/8 1/4 160 120 130 120 140 100 110 100 130 90 100 90 130 90 100 90 120 90 90 80 5/16 190 140 140 130 160 110 120 110 150 110 110 100 150 100 110 100 150 100 110 90 3/8 190 130 140 120 170 110 120 100 160 100 110 100 160 100 110 90 150 100 110 90 3/4 1/4 180 140 140 130 150 110 120 110 140 100 110 100 140 100 110 90 130 90 100 90 5/16 210 150 160 140 180 120 130 120 170 110 120 100 160 110 120 100 160 100 110 100 3/8 210 140 160 130 180 120 130 110 170 110 120 100 170 110 120 100 160 100 110 90 1 1/4 180 140 140 140 160 120 120 120 150 120 120 110 150 110 110 110 150 110 110 100 5/16 230 170 170 160 210 140 150 130 190 130 140 120 190 120 140 120 180 120 130 110 3/8 230 160 170 160 210 130 150 120 200 120 140 110 190 120 140 110 180 110 130 100 1-1/4 1/4 180 140 140 140 160 120 120 120 150 120 120 110 150 110 110 110 150 110 110 100 5/16 230 170 170 160 210 150 150 140 200 140 140 130 200 140 140 130 190 130 140 120 3/8 230 170 170 160 210 150 150 140 200 140 140 130 200 130 140 120 190 120 140 120 1-1/2 1/4 180 140 140 140 160 120 120 120 150 120 120 110 150 110 110 110 150 110 110 100 5/16 230 170 170 160 210 150 150 140 200 140 140 130 200 140 140 130 190 140 140 130 3/8 230 170 170 160 210 150 150 140 200 140 140 130 200 140 140 130 190 140 140 120 7/16 360 260 260 240 320 220 230 200 310 200 210 180 310 190 210 180 300 180 200 160 1/2 460 310 320 280 410 250 290 230 390 220 270 200 390 220 260 200 370 210 250 190 5/8 700 410 500 370 600 340 420 310 560 310 380 280 550 310 380 270 530 290 360 260 3/4 950 550 660 490 830 470 560 410 770 440 510 380 760 430 510 370 730 400 480 360 7/8 1240 720 830 630 1080 560 710 540 1020 490 660 490 1010 470 650 470 970 430 610 430 1 1550 800 1010 780 1360 600 870 600 1290 530 810 530 1280 500 790 500 1230 470 760 470 1-3/4 1/4 180 140 140 140 160 120 120 120 150 120 120 110 150 110 110 110 150 110 110 100 5/16 230 170 170 160 210 150 150 140 200 140 140 130 200 140 140 130 190 140 140 130 3/8 230 170 170 160 210 150 150 140 200 140 140 130 200 140 140 130 190 140 140 120 7/16 360 260 260 240 320 230 230 210 310 210 210 190 310 210 210 190 300 200 200 180 1/2 460 320 320 290 410 270 290 250 390 240 270 220 390 240 260 220 380 220 250 200 5/8 740 440 500 400 660 360 440 320 610 330 420 290 600 320 410 290 570 300 390 270 3/4 1030 580 720 520 890 480 600 430 830 450 550 390 820 440 540 380 780 420 510 360 7/8 1320 740 890 650 1150 630 750 550 1070 570 700 510 1060 550 680 490 1010 500 650 470 1 1630 910 1070 790 1420 700 910 670 1340 610 850 610 1320 590 830 590 1270 550 790 550 2-1/2 1/4 180 140 140 140 160 120 120 120 150 120 120 110 150 110 110 110 150 110 110 100 5/16 230 170 170 160 210 150 150 140 200 140 140 130 200 140 140 130 190 140 140 130 3/8 230 170 170 160 210 150 150 140 200 140 140 130 200 140 140 130 190 140 140 120 7/16 360 260 260 240 320 230 230 210 310 210 210 190 310 210 210 190 300 200 200 180 1/2 460 320 320 290 410 290 290 250 390 270 270 240 390 260 260 230 380 250 250 220 5/8 740 500 500 450 670 430 440 390 640 390 420 350 630 380 410 340 610 360 390 320 3/4 1110 680 740 610 1010 550 650 490 960 500 610 450 950 490 600 430 920 460 580 410 7/8 1550 830 1000 740 1370 690 880 600 1280 630 830 550 1260 620 810 530 1190 580 770 500 1 1940 980 1270 860 1660 830 1080 720 1550 770 990 660 1520 750 970 640 1450 720 920 620 3-1/2 1/4 180 140 140 140 160 120 120 120 150 120 120 110 150 110 110 110 150 110 110 100 5/16 230 170 170 160 210 150 150 140 200 140 140 130 200 140 140 130 190 140 140 130 3/8 230 170 170 160 210 150 150 140 200 140 140 130 200 140 140 130 190 140 140 120 7/16 360 260 260 240 320 230 230 210 310 210 210 190 310 210 210 190 300 200 200 180 1/2 460 320 320 290 410 290 290 250 390 270 270 240 390 260 260 230 380 250 250 220 5/8 740 500 500 450 670 440 440 390 640 420 420 360 630 410 410 360 610 390 390 340 3/4 1110 740 740 650 1010 650 650 560 960 600 610 520 950 580 600 510 920 550 580 490 7/8 1550 990 1000 860 1400 800 880 710 1340 720 830 640 1320 700 810 620 1280 660 780 570 1 2020 1140 1270 1010 1830 930 1120 810 1740 850 1060 740 1730 830 1040 720 1670 790 1000 680 1. Tabulated lateral design values, Z, shall be multiplied by all applicable adjustment factors (see Table 11.3.1). 2. Tabulated lateral design values, Z, are for reduced body diameter lag screws (see Appendix Table L2) inserted in side grain with screw axis perpendicular to wood fibers; screw penetration, p, into the main member equal to 8D; screw bending yield strengths, F yb,of 70,000 psi for D = 1/4", 60,000 psi for D = 5/16", and 45,000 psi for D 3/8". 3. Where the lag screw penetration, p, is less than 8D but not less than 4D, tabulated lateral design values, Z, shall be multiplied by p/8d or lateral design values shall be calculated using the provisions of 12.3 for the reduced penetration. 4. The length of lag screw penetration, p, not including the length of the tapered tip, E (see Appendix Table L2), of the lag screw into the main member shall not be less than 4D. See 12.1.4.6 for minimum length of penetration, p min.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 105 Table 12J (Cont.) Side Member Thickness Lag Screw Diameter LAG SCREWS: Reference Lateral Design Values (Z) for Single Shear (two member) Connections 1,2,3,4 for sawn lumber or SCL with both members of identical specific gravity (tabulated lateral design values are calculated based on an assumed length of lag screw penetration, p, into the main member equal to 8D) G=0.43 Hem-Fir G=0.42 Spruce-Pine-Fir G=0.37 Redwood (open grain) G=0.36 Eastern Softwoods Spruce-Pine-Fir(S) Western Cedars Western Woods G=0.35 Northern Species t s D Z ll Z s Z m Z Z ll Z s Z m Z Z ll Z s Z m Z Z ll Z s Z m Z Z ll Z s Z m Z in. in. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. 1/2 1/4 110 80 80 70 110 80 80 70 100 70 70 60 100 70 70 60 90 70 70 60 5/16 130 90 100 80 130 90 90 80 120 80 90 80 120 80 90 70 120 80 80 70 3/8 140 80 100 80 130 80 90 80 120 60 90 60 120 60 80 60 120 60 80 60 5/8 1/4 120 80 90 80 110 80 90 70 110 70 80 70 100 70 80 60 100 70 70 60 5/16 140 90 100 90 140 90 100 90 130 80 90 80 130 80 90 80 120 80 90 70 3/8 140 90 100 80 140 90 100 80 130 80 90 70 130 70 90 70 120 70 90 70 3/4 1/4 130 90 100 80 120 80 90 80 110 80 80 70 110 70 80 70 110 70 80 70 5/16 150 100 110 90 150 100 110 90 130 90 100 80 130 90 90 80 130 80 90 80 3/8 150 100 110 90 150 90 110 90 140 90 100 80 130 80 90 70 130 80 90 70 1 1/4 140 100 110 90 140 100 100 90 130 90 100 80 130 80 90 80 130 80 90 70 5/16 170 110 130 100 170 110 120 100 150 90 110 90 150 90 110 80 150 90 100 80 3/8 170 100 120 100 170 100 120 90 150 90 110 80 150 90 110 80 150 90 100 80 1-1/4 1/4 140 110 110 100 140 100 100 100 130 100 100 90 130 90 90 90 130 90 90 80 5/16 180 120 130 110 180 120 130 110 170 100 120 100 170 100 120 90 160 100 110 90 3/8 190 120 130 110 180 110 130 100 170 100 120 90 170 100 120 90 170 90 110 80 1-1/2 1/4 140 110 110 100 140 100 100 100 130 100 100 90 130 90 90 90 130 90 90 80 5/16 180 130 130 120 180 130 130 120 170 110 120 110 170 110 120 100 160 110 110 100 3/8 190 130 130 120 180 130 130 110 170 110 120 100 170 110 120 100 170 100 110 90 7/16 290 170 190 150 280 160 190 150 260 140 180 130 260 140 170 130 250 140 170 120 1/2 350 190 240 180 350 190 240 170 310 170 210 150 310 160 210 150 300 160 200 140 5/8 500 280 340 240 490 270 330 240 450 250 300 210 440 240 290 210 430 240 280 200 3/4 700 360 450 330 690 350 440 330 630 290 400 290 620 280 390 280 610 270 380 270 7/8 930 390 580 390 910 380 570 380 850 320 520 320 840 310 510 310 820 290 490 290 1 1180 420 720 420 1160 410 710 410 1080 340 640 340 1070 330 630 330 1050 320 620 320 1-3/4 1/4 140 110 110 100 140 100 100 100 130 100 100 90 130 90 90 90 130 90 90 80 5/16 180 130 130 120 180 130 130 120 170 120 120 110 170 120 120 110 160 110 110 100 3/8 190 130 130 120 180 130 130 110 170 120 120 100 170 120 120 100 170 110 110 100 7/16 290 180 190 160 280 180 190 160 270 160 180 140 260 150 170 140 260 140 170 130 1/2 360 210 240 190 360 200 240 180 340 180 220 160 340 170 220 150 330 170 210 150 5/8 540 290 360 250 530 280 360 250 480 250 320 220 480 250 310 210 460 240 300 210 3/4 740 400 480 340 730 390 470 340 670 330 420 300 660 320 420 300 640 310 410 290 7/8 970 450 610 440 950 440 600 440 880 370 540 370 870 360 530 360 850 330 520 330 1 1210 490 750 490 1200 480 740 480 1110 400 670 400 1090 380 650 380 1070 370 640 370 2-1/2 1/4 140 110 110 100 140 100 100 100 130 100 100 90 130 90 90 90 130 90 90 80 5/16 180 130 130 120 180 130 130 120 170 120 120 110 170 120 120 110 160 110 110 100 3/8 190 130 130 120 180 130 130 110 170 120 120 100 170 120 120 100 170 110 110 100 7/16 290 190 190 170 280 190 190 170 270 180 180 150 260 170 170 150 260 170 170 150 1/2 360 240 240 210 360 240 240 210 340 220 220 190 340 210 220 190 330 200 210 180 5/8 590 330 380 290 580 320 370 290 550 290 340 250 540 280 340 240 530 270 330 240 3/4 890 430 550 380 880 420 540 370 800 380 500 320 780 370 490 320 760 360 480 310 7/8 1130 550 730 470 1110 540 710 460 1010 490 640 420 990 480 620 410 970 470 600 390 1 1380 680 870 580 1360 670 850 570 1240 570 760 510 1220 550 750 500 1190 530 730 490 3-1/2 1/4 140 110 110 100 140 100 100 100 130 100 100 90 130 90 90 90 130 90 90 80 5/16 180 130 130 120 180 130 130 120 170 120 120 110 170 120 120 110 160 110 110 100 3/8 190 130 130 120 180 130 130 110 170 120 120 100 170 120 120 100 170 110 110 100 7/16 290 190 190 170 280 190 190 170 270 180 180 150 260 170 170 150 260 170 170 150 1/2 360 240 240 210 360 240 240 210 340 220 220 190 340 220 220 190 330 210 210 180 5/8 590 380 380 320 580 370 370 320 550 340 340 290 540 330 340 280 530 320 330 280 3/4 890 500 550 440 880 490 540 430 830 430 500 370 820 420 490 370 800 410 480 360 7/8 1240 610 750 530 1220 600 740 520 1150 530 680 460 1140 520 670 450 1110 500 650 430 1 1610 740 950 630 1600 720 940 620 1480 650 860 550 1450 630 850 540 1410 620 830 520 1. Tabulated lateral design values, Z, shall be multiplied by all applicable adjustment factors (see Table 11.3.1). 2. Tabulated lateral design values, Z, are for reduced body diameter lag screws (see Appendix Table L2) inserted in side grain with screw axis perpendicular to wood fibers; screw penetration, p, into the main member equal to 8D; screw bending yield strengths, F yb,of 70,000 psi for D = 1/4", 60,000 psi for D = 5/16", and 45,000 psi for D 3/8". 3. Where the lag screw penetration, p, is less than 8D but not less than 4D, tabulated lateral design values, Z, shall be multiplied by p/8d or lateral design values shall be calculated using the provisions of 12.3 for the reduced penetration. 4. The length of lag screw penetration, p, not including the length of the tapered tip, E (see Appendix Table L2), of the lag screw into the main member shall not be less than 4D. See 12.1.4.6 for minimum length of penetration, p min. LAG SCREWS DOWEL-TYPE FASTENERS 12 AMERICAN WOOD COUINCIL

106 DOWEL-TYPE FASTENERS LAG SCREWS Table 12K Side Member Thickness Lag Screw Diameter LAG SCREWS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections 1,2,3,4 for sawn lumber or SCL with ASTM A653, Grade 33 steel side plate (for t s <1/4") or ASTM A 36 steel side plate (for t s =1/4") (tabulated lateral design values are calculated based on an assumed length of lag screw penetration, p, into the main member equal to 8D) G=0.67 Red Oak G=0.55 Mixed Maple Southern Pine G=0.5 Douglas Fir-Larch G=0.49 Douglas Fir-Larch (N) G=0.46 Douglas Fir(S) Hem-Fir(N) t s D Z ll Z Z ll Z Z ll Z Z ll Z Z ll Z Z ll Z Z ll Z Z ll Z Z ll Z Z ll Z in. in. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. 0.075 1/4 170 130 160 120 150 110 150 110 150 100 140 100 140 100 130 90 130 90 130 90 (14 gage) 5/16 220 160 200 140 190 130 190 130 190 130 180 120 180 120 170 110 170 110 160 100 3/8 220 160 200 140 200 130 190 130 190 120 180 120 180 120 170 110 170 100 170 100 0.105 1/4 180 140 170 130 160 120 160 120 160 110 150 110 150 110 140 100 140 100 140 90 (12 gage) 5/16 230 170 210 150 200 140 200 140 190 130 190 130 190 120 180 110 170 110 170 110 3/8 230 160 210 140 200 140 200 130 200 130 190 120 190 120 180 110 180 110 170 110 0.120 1/4 190 150 180 130 170 120 170 120 160 120 160 110 160 110 150 100 150 100 140 100 (11 gage) 5/16 230 170 210 150 210 140 200 140 200 140 190 130 190 130 180 120 180 120 180 110 3/8 240 170 220 150 210 140 210 140 200 130 200 130 190 120 180 110 180 110 180 110 0.134 1/4 200 150 180 140 180 130 170 130 170 120 160 120 160 110 150 110 150 100 150 100 (10 gage) 5/16 240 180 220 160 210 150 210 140 200 140 200 130 200 130 190 120 180 120 180 120 3/8 240 170 220 150 220 140 210 140 210 140 200 130 200 130 190 120 190 120 180 110 0.179 1/4 220 170 210 150 200 150 200 140 190 140 190 130 190 130 180 120 170 120 170 120 (7 gage) 5/16 260 190 240 170 230 160 230 160 230 150 220 150 220 150 210 130 200 130 200 130 3/8 270 190 250 170 240 160 240 160 230 150 220 140 220 140 210 130 210 130 200 130 0.239 1/4 240 180 220 160 210 150 210 150 200 140 190 140 190 130 180 120 180 120 180 120 (3 gage) 5/16 300 220 280 190 270 180 260 180 260 170 250 160 250 160 230 150 230 150 230 140 3/8 310 220 280 190 270 180 270 180 260 170 250 160 250 160 240 140 230 140 230 140 7/16 420 290 390 260 380 240 370 240 360 230 350 220 350 220 330 200 330 200 320 190 1/2 510 340 470 300 460 290 450 280 440 270 430 260 420 260 400 240 400 230 390 230 5/8 770 490 710 430 680 400 680 400 660 380 640 370 630 360 600 330 590 330 580 320 3/4 1110 670 1020 590 980 560 970 550 950 530 920 500 910 500 860 450 850 450 840 440 7/8 1510 880 1390 780 1330 730 1320 710 1280 690 1250 650 1230 650 1170 590 1160 590 1140 570 1 1940 1100 1780 960 1710 910 1700 890 1650 860 1600 820 1590 810 1500 740 1480 730 1460 710 1/4 1/4 240 180 220 160 210 150 210 150 200 140 200 140 190 130 180 120 180 120 180 120 5/16 310 220 280 200 270 180 270 180 260 170 250 170 250 160 230 150 230 150 230 140 3/8 320 220 290 190 280 180 270 180 270 170 260 160 250 160 240 150 240 140 230 140 7/16 480 320 440 280 420 270 420 260 410 250 390 240 390 230 370 220 360 210 360 210 1/2 580 390 540 340 520 320 510 320 500 310 480 290 480 290 460 270 450 260 440 260 5/8 850 530 780 470 750 440 740 440 720 420 700 400 690 400 660 370 650 360 640 350 3/4 1200 730 1100 640 1060 600 1050 590 1020 570 990 540 980 530 930 490 920 480 900 470 7/8 1600 930 1470 820 1410 770 1400 750 1360 720 1320 690 1310 680 1240 630 1220 620 1200 600 1 2040 1150 1870 1000 1800 950 1780 930 1730 900 1680 850 1660 840 1570 770 1550 760 1530 740 G=0.42 Spruce-Pine-Fir G=0.37 Redwood (open grain) G=0.36 Eastern Softwoods Spruce-Pine-Fir(S) Western Cedars Western Woods 1. Tabulated lateral design values, Z, shall be multiplied by all applicable adjustment factors (see Table 11.3.1). 2. Tabulated lateral design values, Z, are for reduced body diameter lag screws (see Appendix Table L2) inserted in side grain with screw axis perpendicular to wood fibers; screw penetration, p, into the main member equal to 8D; dowel bearing strengths, F e, of 61,850 psi for ASTM A653, Grade 33 steel and 87,000 psi for ASTM A36 steel and screw bending yield strengths, F yb, of 70,000 psi for D = 1/4", 60,000 psi for D = 5/16", and 45,000 psi for D 3/8". 3. Where the lag screw penetration, p, is less than 8D but not less than 4D, tabulated lateral design values, Z, shall be multiplied by p/8d or lateral design values shall be calculated using the provisions of 12.3 for the reduced penetration. 4. The length of lag screw penetration, p, not including the length of the tapered tip, E (see Appendix Table L2), of the lag screw into the main member shall not be less than 4D. See 12.1.4.6 for minimum length of penetration, p min. G=0.43 Hem-Fir G=0.35 Northern Species

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 107 Table 12L Side Member Thickness Wood Screw Diameter Wood Screw Number WOOD SCREWS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections 1,2,3 for sawn lumber or SCL with both members of identical specific gravity (tabulated lateral design values are calculated based on an assumed length of wood screw penetration, p, into the main member equal to 10D) G=0.67 Red Oak G=0.55 Mixed Maple Southern Pine G=0.5 Douglas Fir-Larch G=0.49 Douglas Fir-Larch(N) G=0.46 Douglas Fir(S) Hem-Fir(N) G=0.43 Hem-Fir G=0.42 Spruce-Pine-Fir G=0.37 Redwood (open grain) G=0.36 Eastern Softwoods Spruce-Pine-Fir(S) Western Cedars Western Woods t s D in. in. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. 1/2 0.138 6 88 67 59 57 53 49 47 41 40 38 0.151 7 96 74 65 63 59 54 52 45 44 42 0.164 8 107 82 73 71 66 61 59 51 50 48 0.177 9 121 94 83 81 76 70 68 59 58 56 0.190 10 130 101 90 87 82 75 73 64 63 60 0.216 12 156 123 110 107 100 93 91 79 78 75 0.242 14 168 133 120 117 110 102 99 87 86 83 5/8 0.138 6 94 76 66 64 59 53 52 44 43 41 0.151 7 104 83 72 70 64 58 56 48 47 45 0.164 8 120 92 80 77 72 65 63 54 53 51 0.177 9 136 103 91 88 81 74 72 62 61 58 0.190 10 146 111 97 94 88 80 78 67 65 63 0.216 12 173 133 117 114 106 97 95 82 80 77 0.242 14 184 142 126 123 115 106 103 89 87 84 3/4 0.138 6 94 79 72 71 65 58 57 47 46 44 0.151 7 104 87 80 77 71 64 62 52 50 48 0.164 8 120 101 88 85 78 71 69 58 56 54 0.177 9 142 114 99 96 88 80 78 66 64 61 0.190 10 153 122 107 103 95 86 83 71 69 66 0.216 12 192 144 126 122 113 103 100 86 84 80 0.242 14 203 154 135 131 122 111 108 93 91 87 1 0.138 6 94 79 72 71 67 63 61 55 54 51 0.151 7 104 87 80 78 74 69 68 60 59 56 0.164 8 120 101 92 90 85 80 78 67 65 62 0.177 9 142 118 108 106 100 94 90 75 73 70 0.190 10 153 128 117 114 108 101 97 81 78 75 0.216 12 193 161 147 143 131 118 114 96 93 89 0.242 14 213 178 157 152 139 126 122 102 100 95 1-1/4 0.138 6 94 79 72 71 67 63 61 55 54 52 0.151 7 104 87 80 78 74 69 68 60 59 57 0.164 8 120 101 92 90 85 80 78 70 68 66 0.177 9 142 118 108 106 100 94 92 82 80 78 0.190 10 153 128 117 114 108 101 99 88 87 84 0.216 12 193 161 147 144 137 128 125 108 105 100 0.242 14 213 178 163 159 151 141 138 115 111 106 1-1/2 0.138 6 94 79 72 71 67 63 61 55 54 52 0.151 7 104 87 80 78 74 69 68 60 59 57 0.164 8 120 101 92 90 85 80 78 70 68 66 0.177 9 142 118 108 106 100 94 92 82 80 78 0.190 10 153 128 117 114 108 101 99 88 87 84 0.216 12 193 161 147 144 137 128 125 111 109 106 0.242 14 213 178 163 159 151 141 138 123 120 117 1-3/4 0.138 6 94 79 72 71 67 63 61 55 54 52 0.151 7 104 87 80 78 74 69 68 60 59 57 0.164 8 120 101 92 90 85 80 78 70 68 66 0.177 9 142 118 108 106 100 94 92 82 80 78 0.190 10 153 128 117 114 108 101 99 88 87 84 0.216 12 193 161 147 144 137 128 125 111 109 106 0.242 14 213 178 163 159 151 141 138 123 120 117 1. Tabulated lateral design values, Z, shall be multiplied by all applicable adjustment factors (see Table 11.3.1). 2. Tabulated lateral design values, Z, are for rolled thread wood screws (see Appendix Table L3) inserted in side grain with screw axis perpendicular to wood fibers; screw penetration, p, into the main member equal to 10D; and screw bending yield strengths, F yb, of 100,000 psi for 0.099" D 0.142", 90,000 psi for 0.142" < D 0.177", 80,000 psi for 0.177" < D 0.236", and 70,000 psi for 0.236" < D 0.273". 3. Where the wood screw penetration, p, is less than 10D but not less than 6D, tabulated lateral design values, Z, shall be multiplied by p/10d or lateral design values shall be calculated using the provisions of 12.3 for the reduced penetration. G=0.35 Northern Species WOOD SCREWS DOWEL-TYPE FASTENERS 12

108 DOWEL-TYPE FASTENERS WOOD SCREWS Table 12M Side Member Thickness Wood Screw Diameter WOOD SCREWS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections 1,2,3 for sawn lumber or SCL with ASTM 653, Grade 33 steel side plate (tabulated lateral design values are calculated based on an assumed length of wood screw penetration, p, into the main member equal to 10D) Wood Screw Number G=0.67 Red Oak G=0.55 Mixed Maple Southern Pine G=0.5 Douglas Fir-Larch G=0.49 Douglas Fir-Larch(N) G=0.46 Douglas Fir(S) Hem-Fir(N) t s D in. in. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. 0.036 0.138 6 89 76 70 69 66 62 60 54 53 52 (20 gage) 0.151 7 99 84 78 76 72 68 67 60 59 57 0.164 8 113 97 89 87 83 78 77 69 67 66 0.048 0.138 6 90 77 71 70 67 63 61 55 54 53 (18 gage) 0.151 7 100 85 79 77 74 69 68 61 60 58 0.164 8 114 98 90 89 84 79 78 70 69 67 0.060 0.138 6 92 79 73 72 68 64 63 57 56 54 (16 gage) 0.151 7 101 87 81 79 75 71 70 63 61 60 0.164 8 116 100 92 90 86 81 79 71 70 68 0.177 9 136 116 107 105 100 94 93 83 82 79 0.190 10 146 125 116 114 108 102 100 90 88 86 0.075 0.138 6 95 82 76 75 71 67 66 59 58 57 (14 gage) 0.151 7 105 90 84 82 78 74 72 65 64 62 0.164 8 119 103 95 93 89 84 82 74 73 71 0.177 9 139 119 110 108 103 97 95 86 84 82 0.190 10 150 128 119 117 111 105 103 92 91 88 0.216 12 186 159 147 145 138 130 127 114 112 109 0.242 14 204 175 162 158 151 142 139 125 123 120 0.105 0.138 6 104 90 84 82 79 74 73 66 65 63 (12 gage) 0.151 7 114 99 92 90 86 81 80 72 71 69 0.164 8 129 111 103 102 97 92 90 81 80 77 0.177 9 148 128 119 116 111 105 103 93 91 89 0.190 10 160 138 128 125 120 113 111 100 98 96 0.216 12 196 168 156 153 146 138 135 122 120 116 0.242 14 213 183 170 167 159 150 147 132 130 126 0.120 0.138 6 110 95 89 87 83 79 77 70 68 67 (11 gage) 0.151 7 120 104 97 95 91 86 84 76 75 73 0.164 8 135 117 109 107 102 96 94 85 84 82 0.177 9 154 133 124 121 116 110 107 97 95 93 0.190 10 166 144 133 131 125 118 116 104 103 100 0.216 12 202 174 162 159 152 143 140 126 124 121 0.242 14 219 189 175 172 164 155 152 137 134 131 0.134 0.138 6 116 100 93 92 88 83 81 73 72 70 (10 gage) 0.151 7 126 110 102 100 96 91 89 80 79 77 0.164 8 141 122 114 112 107 101 99 89 88 86 0.177 9 160 139 129 127 121 114 112 101 100 97 0.190 10 173 149 139 136 130 123 121 109 107 104 0.216 12 209 180 167 164 157 148 145 131 129 126 0.242 14 226 195 181 177 169 160 157 141 139 135 0.179 0.138 6 126 107 99 97 92 86 84 76 74 72 (7 gage) 0.151 7 139 118 109 107 102 95 93 84 82 80 0.164 8 160 136 126 123 117 110 108 96 95 92 0.177 9 184 160 148 145 138 129 127 113 111 108 0.190 10 198 172 159 156 149 140 137 122 120 117 0.216 12 234 203 189 186 178 168 165 149 146 143 0.242 14 251 217 202 198 190 179 176 159 156 152 0.239 0.138 6 126 107 99 97 92 86 84 76 74 72 (3 gage) 0.151 7 139 118 109 107 102 95 93 84 82 80 0.164 8 160 136 126 123 117 110 108 96 95 92 0.177 9 188 160 148 145 138 129 127 113 111 108 0.190 10 204 173 159 156 149 140 137 122 120 117 0.216 12 256 218 201 197 187 176 172 154 151 147 0.242 14 283 241 222 217 207 194 190 170 167 162 1. Tabulated lateral design values, Z, shall be multiplied by all applicable adjustment factors (see Table 11.3.1). 2. Tabulated lateral design values, Z, are for rolled thread wood screws (see Appendix L) inserted in side grain with screw axis perpendicular to wood fibers; screw penetration, p, into the main member equal to 10D; dowel bearing strength, F e, of 61,850 psi for ASTM A653, Grade 33 steel and screw bending yield strengths, F yb, of 100,000 psi for 0.099" D 0.142", 90,000 psi for 0.142" < D 0.177", 80,000 psi for 0.177"< D 0.236", 70,000 psi for 0.236" < D 0.273". 3. Where the wood screw penetration, p, is less than 10D but not less than 6D, tabulated lateral design values, Z, shall be multiplied by p/10d or lateral design values shall be calculated using the provisions of 12.3 for the reduced penetration. G=0.43 Hem-Fir G=0.42 Spruce-Pine-Fir G=0.37 Redwood (open grain) G=0.36 Eastern Softwoods Spruce-Pine-Fir(S) Western Cedars Western Woods G=0.35 Northern Species

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 109 Table 12N Side Member Thickness Nail Diameter Common Wire Nail COMMON, BOX, or SINKER STEEL WIRE NAILS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections 1,2,3 for sawn lumber or SCL with both members of identical specific gravity (tabulated lateral design values are calculated based on an assumed length of nail penetration, p, into the main member equal to 10D) Box Nail Sinker Nail G=0.67 Red Oak G=0.55 Mixed Maple Southern Pine G=0.5 Douglas Fir-Larch G=0.49 Douglas Fir-Larch (N) G=0.46 Douglas Fir(S) Hem-Fir(N) G=0.43 Hem-Fir G=0.42 Spruce-Pine-Fir G=0.37 Redwood (open grain) G=0.36 Eastern Softwoods Spruce-Pine-Fir(S) Western Cedars Western Woods G=0.35 Northern Species NAILS t s D in. in. Pennyweight lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. 3/4 0.099 6d 7d 73 61 55 54 51 48 47 39 38 36 0.113 6d 8d 8d 94 79 72 71 65 58 57 47 46 44 0.120 10d 107 89 80 77 71 64 62 52 50 48 0.128 10d 121 101 87 84 78 70 68 57 56 54 0.131 8d 127 104 90 87 80 73 70 60 58 56 0.135 16d 12d 135 108 94 91 84 76 74 63 61 58 0.148 10d 20d 16d 154 121 105 102 94 85 83 70 69 66 0.162 16d 40d 183 138 121 117 108 99 96 82 80 77 0.177 20d 200 153 134 130 121 111 107 92 90 87 0.192 20d 30d 206 157 138 134 125 114 111 96 93 90 0.207 30d 40d 216 166 147 143 133 122 119 103 101 97 0.225 40d 229 178 158 154 144 132 129 112 110 106 0.244 50d 60d 234 182 162 158 147 136 132 115 113 109 1 0.099 6d 7d 73 61 55 54 51 48 47 42 41 40 0.113 6d 4 8d 8d 94 79 72 71 67 63 61 55 54 51 0.120 10d 107 89 81 80 76 71 69 60 59 56 0.128 10d 121 101 93 91 86 80 79 66 64 61 0.131 8d 127 106 97 95 90 84 82 68 66 63 0.135 16d 12d 135 113 103 101 96 89 86 71 69 66 0.148 10d 20d 16d 154 128 118 115 109 99 96 80 77 74 0.162 16d 40d 184 154 141 137 125 113 109 91 89 85 0.177 20d 213 178 155 150 138 125 121 102 99 95 0.192 20d 30d 222 183 159 154 142 128 124 105 102 98 0.207 30d 40d 243 192 167 162 149 135 131 111 109 104 0.225 40d 268 202 177 171 159 144 140 120 117 112 0.244 50d 60d 274 207 181 175 162 148 143 123 120 115 1-1/4 0.099 6d 4 7d 4 73 61 55 54 51 48 47 42 41 40 0.113 6d 4 8d 8d 4 94 79 72 71 67 63 61 55 54 52 0.120 10d 107 89 81 80 76 71 69 62 60 59 0.128 10d 121 101 93 91 86 80 79 70 69 67 0.131 8d 4 127 106 97 95 90 84 82 73 72 70 0.135 16d 12d 135 113 103 101 96 89 88 78 76 74 0.148 10d 20d 16d 154 128 118 115 109 102 100 89 87 84 0.162 16d 40d 184 154 141 138 131 122 120 103 100 95 0.177 20d 213 178 163 159 151 141 136 113 110 105 0.192 20d 30d 222 185 170 166 157 145 140 116 113 108 0.207 30d 40d 243 203 186 182 169 152 147 123 119 114 0.225 40d 268 224 200 193 177 160 155 130 127 121 0.244 50d 60d 276 230 204 197 181 163 158 133 129 124 1-1/2 0.099 7d 4 73 61 55 54 51 48 47 42 41 40 0.113 8d 4 8d 4 94 79 72 71 67 63 61 55 54 52 0.120 10d 107 89 81 80 76 71 69 62 60 59 0.128 10d 121 101 93 91 86 80 79 70 69 67 0.131 8d 4 127 106 97 95 90 84 82 73 72 70 0.135 16d 12d 135 113 103 101 96 89 88 78 76 74 0.148 10d 20d 16d 154 128 118 115 109 102 100 89 87 84 0.162 16d 40d 184 154 141 138 131 122 120 106 104 101 0.177 20d 213 178 163 159 151 141 138 123 121 117 0.192 20d 30d 222 185 170 166 157 147 144 128 126 120 0.207 30d 40d 243 203 186 182 172 161 158 135 131 125 0.225 40d 268 224 205 201 190 178 172 143 138 132 0.244 50d 60d 276 230 211 206 196 181 175 146 141 135 1-3/4 0.113 8d 4 94 79 72 71 67 63 61 55 54 52 0.120 10d 4 107 89 81 80 76 71 69 62 60 59 0.128 10d 4 121 101 93 91 86 80 79 70 69 67 0.135 16d 12d 135 113 103 101 96 89 88 78 76 74 0.148 10d 4 20d 16d 154 128 118 115 109 102 100 89 87 84 0.162 16d 40d 184 154 141 138 131 122 120 106 104 101 0.177 20d 213 178 163 159 151 141 138 123 121 117 0.192 20d 30d 222 185 170 166 157 147 144 128 126 122 0.207 30d 40d 243 203 186 182 172 161 158 140 137 133 0.225 40d 268 224 205 201 190 178 174 155 151 144 0.244 50d 60d 276 230 211 206 196 183 179 159 154 147 1. Tabulated lateral design values, Z, shall be multiplied by all applicable adjustment factors (see Table 11.3.1). 2. Tabulated lateral design values, Z, are for common, box, or sinker steel wire nails (see Appendix Table L4) inserted in side grain with nail axis perpendicular to wood fibers; nail penetration, p, into the main member equal to 10D; and nail bending yield strengths, F yb, of 100,000 psi for 0.099" D 0.142", 90,000 psi for 0.142" < D 0.177", 80,000 psi for 0.177" < D 0.236", and 70,000 psi for 0.236" < D 0.273". 3. Where the nail or spike penetration, p, is less than 10D but not less than 6D, tabulated lateral design values, Z, shall be multiplied by p/10d or lateral design values shall be calculated using the provisions of 12.3 for the reduced penetration. 4. Nail length is insufficient to provide 10D penetration. Tabulated lateral design values, Z, shall be adjusted per footnote 3. DOWEL-TYPE FASTENERS 12

110 DOWEL-TYPE FASTENERS NAILS Table 12P Side Member Thickness Nail Diameter Common Wire Nail COMMON, BOX, or SINKER STEEL WIRE NAILS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections 1,2,3 for sawn lumber or SCL with ASTM 653, Grade 33 steel side plate (tabulated lateral design values are calculated based on an assumed length of nail penetration, p, into the main member equal to 10D) Box Nail Sinker Nail G=0.67 Red Oak G=0.55 Mixed Maple Southern Pine G=0.5 Douglas Fir-Larch G=0.49 Douglas Fir-Larch (N) G=0.46 Douglas Fir(S) Hem-Fir(N) G=0.43 Hem-Fir G=0.42 Spruce-Pine-Fir G=0.37 Redwood (open grain) G=0.36 Eastern Softwoods Spruce-Pine-Fir(S) Western Cedars Western Woods G=0.35 Northern Species t s D in. in. Pennyweight lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. 0.036 0.099 6d 7d 69 59 54 53 51 48 47 42 41 40 (20 gage) 0.113 6d 8d 8d 89 76 70 69 66 62 60 54 53 52 0.120 10d 100 86 79 77 74 69 68 61 60 58 0.128 10d 114 97 90 88 84 79 77 69 68 66 0.131 8d 120 102 94 92 88 82 81 72 71 69 0.135 16d 12d 127 108 100 98 93 87 86 77 75 73 0.148 10d 20d 16d 145 123 114 111 106 100 98 87 86 83 0.048 0.099 6d 7d 70 60 55 54 52 49 48 43 42 41 (18 gage) 0.113 6d 8d 8d 90 77 71 70 67 63 61 55 54 53 0.120 10d 101 87 80 78 75 70 69 62 61 59 0.128 10d 115 98 91 89 85 80 78 70 69 67 0.131 8d 120 103 95 93 89 83 82 73 72 70 0.135 16d 12d 128 109 101 99 94 88 87 78 76 74 0.148 10d 20d 16d 145 124 115 112 107 101 99 88 87 84 0.162 16d 40d 174 148 137 134 128 120 118 105 104 101 0.177 20d 201 171 158 155 147 138 136 122 119 116 0.192 20d 30d 209 178 164 161 153 144 141 126 124 121 0.207 30d 40d 229 195 179 176 167 157 154 138 136 132 0.060 0.099 6d 7d 72 62 57 56 54 51 50 45 44 43 (16 gage) 0.113 6d 8d 8d 92 79 73 72 68 64 63 57 56 54 0.120 10d 103 88 82 80 76 72 71 63 62 61 0.128 10d 117 100 92 91 86 81 80 72 70 68 0.131 8d 122 104 97 95 90 85 83 75 73 71 0.135 16d 12d 129 111 102 100 96 90 88 79 78 76 0.148 10d 20d 16d 147 126 116 114 109 102 100 90 88 86 0.162 16d 40d 175 150 138 135 129 121 119 107 105 102 0.177 20d 202 172 159 156 149 140 137 123 121 117 0.192 20d 30d 210 179 165 162 154 145 142 128 125 122 0.207 30d 40d 229 195 180 177 168 158 155 139 137 133 0.225 40d 253 215 199 195 185 174 171 153 150 146 0.244 50d 60d 260 221 204 200 191 179 176 157 155 150 0.075 0.099 6d 7d 75 65 60 59 56 53 52 47 46 45 (14 gage) 0.113 6d 8d 8d 95 82 76 75 71 67 66 59 58 57 0.120 10d 106 91 85 83 79 75 73 66 65 63 0.128 10d 120 103 95 93 89 84 82 74 73 71 0.131 8d 125 107 99 97 93 88 86 77 76 74 0.135 16d 12d 132 113 105 103 98 93 91 82 80 78 0.148 10d 20d 16d 150 129 119 117 111 105 103 92 91 88 0.162 16d 40d 178 152 141 138 132 124 122 109 107 104 0.177 20d 204 175 162 158 151 142 139 125 123 120 0.192 20d 30d 212 182 168 165 157 148 145 130 128 124 0.207 30d 40d 231 198 183 179 171 161 157 141 139 135 0.225 40d 254 217 201 197 187 176 173 155 152 148 0.244 50d 60d 261 223 206 202 193 181 178 159 156 152 0.105 0.099 6d 7d 84 73 68 67 64 60 59 53 53 51 (12 gage) 0.113 6d 8d 8d 104 90 84 82 79 74 73 66 65 63 0.120 10d 115 100 93 91 87 82 80 73 71 69 0.128 10d 129 111 103 101 97 91 90 81 79 77 0.131 8d 134 116 107 105 101 95 93 84 82 80 0.135 16d 12d 141 122 113 111 106 100 98 88 87 84 0.148 10d 20d 16d 159 137 127 125 119 113 110 99 98 95 0.162 16d 40d 187 161 149 146 140 132 129 116 114 111 0.177 20d 213 183 169 166 159 149 147 132 130 126 0.192 20d 30d 220 189 175 172 164 155 152 137 134 131 0.207 30d 40d 238 205 190 186 177 167 164 147 145 141 0.225 40d 260 223 207 203 193 182 179 161 158 153 0.244 50d 60d 268 230 212 208 199 187 183 165 162 158 1. Tabulated lateral design values, Z, shall be multiplied by all applicable adjustment factors (see Table 11.3.1). 2. Tabulated lateral design values, Z, are for common, box, or sinker steel wire nails (see Appendix Table L4) inserted in side grain with nail axis perpendicular to wood fibers; nail penetration, p, into the main member equal to 10D; dowel bearing strength, F e, of 61,850 psi for ASTM A653, Grade 33 steel and nail bending yield strengths, F yb, of 100,000 psi for 0.099" D 0.142", 90,000 psi for 0.142" < D 0.177", 80,000 psi for 0.177" < D 0.236", 70,000 psi for 0.236" < D 0.273". 3. Where the nail or spike penetration, p, is less than 10D but not less than 6D, tabulated lateral design values, Z, shall be multiplied by p/10d or lateral design values shall be calculated using the provisions of 12.3 for the reduced penetration.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 111 Table 12P (Cont.) Side Member Thickness Nail Diameter Common Wire Nail COMMON, BOX, or SINKER STEEL WIRE NAILS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections 1,2,3 for sawn lumber or SCL with ASTM 653, Grade 33 steel side plate (tabulated lateral design values are calculated based on an assumed length of nail penetration, p, into the main member equal to 10D) Box Nail Sinker Nail G=0.67 Red Oak G=0.55 Mixed Maple Southern Pine G=0.5 Douglas Fir-Larch G=0.49 Douglas Fir-Larch (N) G=0.46 Douglas Fir(S) Hem-Fir(N) G=0.43 Hem-Fir G=0.42 Spruce-Pine-Fir G=0.37 Redwood (open grain) G=0.36 Eastern Softwoods Spruce-Pine-Fir(S) Western Cedars Western Woods G=0.35 Northern Species NAILS t s D in. in. Pennyweight lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. 0.120 0.099 6d 7d 90 78 72 71 68 64 63 57 56 53 (11 gage) 0.113 6d 8d 8d 110 95 89 87 83 79 77 70 68 66 0.120 10d 121 105 97 96 91 86 85 76 75 73 0.128 10d 134 116 108 106 101 96 94 85 83 81 0.131 8d 140 121 112 110 105 99 97 88 86 84 0.135 16d 12d 147 127 118 116 110 104 102 92 91 88 0.148 10d 20d 16d 165 143 133 130 124 117 115 104 102 99 0.162 16d 40d 193 166 154 152 145 137 134 121 119 115 0.177 20d 218 188 174 171 163 154 151 136 134 130 0.192 20d 30d 226 195 181 177 169 159 156 141 138 135 0.207 30d 40d 244 210 194 191 182 172 168 151 149 145 0.225 40d 265 228 211 207 198 186 183 164 161 157 0.244 50d 60d 272 234 217 213 203 191 187 169 166 161 0.134 0.099 6d 7d 95 82 76 74 71 66 65 58 56 54 (10 gage) 0.113 6d 8d 8d 116 100 93 92 88 83 81 73 72 69 0.120 10d 127 110 102 100 96 91 89 80 79 76 0.128 10d 140 122 113 111 106 100 98 89 87 85 0.131 8d 146 126 117 115 110 104 102 92 90 88 0.135 16d 12d 153 132 123 121 115 109 107 96 95 92 0.148 10d 20d 16d 172 148 138 135 129 122 120 108 106 104 0.162 16d 40d 199 172 160 157 150 142 139 125 123 120 0.177 20d 224 194 180 176 169 159 156 141 138 135 0.192 20d 30d 232 200 186 182 174 164 161 145 143 139 0.207 30d 40d 249 215 199 196 187 176 173 156 153 149 0.225 40d 270 233 216 212 202 191 187 168 165 161 0.244 50d 60d 277 239 221 217 207 195 192 173 170 165 0.179 0.099 6d 7d 97 82 76 74 71 66 65 58 56 54 (7 gage) 0.113 6d 8d 8d 126 107 99 97 92 86 84 76 74 70 0.120 10d 142 121 111 109 104 97 95 85 83 79 0.128 10d 161 137 126 124 118 111 108 97 94 90 0.131 8d 168 144 132 130 123 116 114 102 99 94 0.135 16d 12d 175 152 141 138 131 123 121 108 105 100 0.148 10d 20d 16d 195 170 158 155 148 140 137 123 121 117 0.162 16d 40d 224 194 180 177 169 160 157 142 140 136 0.177 20d 249 215 200 197 188 178 174 157 155 151 0.192 20d 30d 256 222 206 203 194 183 179 162 159 155 0.207 30d 40d 272 236 219 215 205 194 190 172 169 164 0.225 40d 292 252 234 230 220 207 203 184 180 176 0.244 50d 60d 299 258 240 235 225 212 208 188 185 180 0.239 0.099 6d 7d 97 82 76 74 71 66 65 58 56 54 (3 gage) 0.113 6d 8d 8d 126 107 99 97 92 86 84 76 74 70 0.120 10d 142 121 111 109 104 97 95 85 83 79 0.128 10d 161 137 126 124 118 111 108 97 94 90 0.131 8d 169 144 132 130 123 116 114 102 99 94 0.135 16d 12d 180 153 141 138 131 123 121 108 105 100 0.148 10d 20d 16d 205 174 160 157 149 140 137 123 121 117 0.162 16d 40d 245 209 192 188 179 168 165 147 145 140 0.177 20d 284 241 222 218 207 195 191 170 167 162 0.192 20d 30d 295 251 231 227 216 202 198 177 174 169 0.207 30d 40d 310 270 251 246 236 222 217 194 191 185 0.225 40d 328 285 265 260 249 235 231 209 205 200 0.244 50d 60d 336 291 271 266 254 240 236 213 210 204 1. Tabulated lateral design values, Z, shall be multiplied by all applicable adjustment factors (see Table 11.3.1). 2. Tabulated lateral design values, Z, are for common, box, or sinker steel wire nails (see Appendix Table L4) inserted in side grain with nail axis perpendicular to wood fibers; nail penetration, p, into the main member equal to 10D; dowel bearing strength, F e, of 61,850 psi for ASTM A653, Grade 33 steel and nail bending yield strengths, F yb, of 100,000 psi for 0.099" D 0.142", 90,000 psi for 0.142" < D 0.177", 80,000 psi for 0.177" < D 0.236", 70,000 psi for 0.236" < D 0.273". 3. Where the nail or spike penetration, p, is less than 10D but not less than 6D, tabulated lateral design values, Z, shall be multiplied by p/10d or lateral design values shall be calculated using the provisions of 12.3 for the reduced penetration. DOWEL-TYPE FASTENERS 12

112 DOWEL-TYPE FASTENERS NAILS Table 12Q Side Member Thickness t s Nail Diameter D COMMON, BOX, or SINKER STEEL WIRE NAILS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections 1,2,3 for sawn lumber or SCL with wood structural panel side members with an effective G=0.50 (tabulated lateral design values are calculated based on an assumed length of nail penetration, p, into the main member equal to 10D) Common Wire Nail Box Nail Sinker Nail G=0.67 Red Oak G=0.55 Mixed Maple Southern Pine G=0.5 Douglas Fir-Larch G=0.49 Douglas Fir-Larch (N) in. in. Pennyweight lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. 3/8 0.099 6d 7d 47 45 43 43 42 40 40 38 37 37 0.113 6d 8d 8d 60 56 54 54 52 51 50 47 47 46 0.120 10d 67 62 60 60 58 56 56 52 52 51 0.128 10d 75 70 68 67 65 63 63 59 58 57 0.131 8d 78 73 71 70 68 66 65 61 61 60 0.135 16d 12d 83 78 75 74 72 70 69 65 64 63 0.148 10d 20d 16d 94 88 85 84 82 79 78 73 72 71 7/16 0.099 6d 7d 50 47 45 45 44 43 42 40 40 39 0.113 6d 8d 8d 62 58 56 56 55 53 52 49 49 48 0.120 10d 69 65 63 62 60 59 58 55 54 53 0.128 10d 77 72 70 69 68 66 65 61 60 59 0.131 8d 80 75 73 72 70 68 67 63 63 62 0.135 16d 12d 85 80 77 76 74 72 71 67 66 65 0.148 10d 20d 16d 96 90 87 86 84 81 80 76 75 73 0.162 16d 40d 114 106 102 101 99 96 95 89 88 86 15/32 0.099 6d 7d 51 48 47 46 45 44 44 41 41 40 0.113 6d 8d 8d 64 60 58 57 56 54 54 51 50 49 0.120 10d 70 66 64 63 62 60 59 56 55 54 0.128 10d 78 74 71 71 69 67 66 62 62 61 0.131 8d 82 77 74 73 72 70 69 65 64 63 0.135 16d 12d 86 81 78 77 76 73 72 68 67 66 0.148 10d 20d 16d 97 91 88 87 85 83 82 77 76 75 0.162 16d 40d 115 108 104 103 100 97 96 90 89 88 19/32 0.099 6d 7d 58 55 53 53 51 50 50 47 46 46 0.113 6d 8d 8d 70 66 64 64 62 61 60 57 56 55 0.120 10d 77 73 70 70 68 66 66 62 61 60 0.128 10d 85 80 78 77 75 73 72 68 68 67 0.131 8d 88 83 80 80 78 76 75 71 70 69 0.135 16d 12d 93 87 84 84 82 79 79 74 73 72 0.148 10d 20d 16d 104 98 95 94 92 89 88 83 82 81 0.162 16d 40d 121 114 110 109 107 103 102 96 95 94 0.177 20d 137 128 124 123 120 116 115 108 107 105 0.192 20d 30d 142 133 128 127 124 120 119 112 111 109 23/32 0.099 6d 7d 62 58 55 55 53 51 51 47 47 46 0.113 6d 8d 8d 78 74 72 71 69 67 66 62 61 60 0.120 10d 85 80 78 77 76 73 73 69 68 67 0.128 10d 93 88 85 85 83 80 80 75 75 74 0.131 8d 96 91 88 87 86 83 82 78 77 76 0.135 16d 12d 101 95 92 91 89 87 86 81 81 79 0.148 10d 20d 16d 113 106 103 102 100 97 96 91 90 89 0.162 16d 40d 130 122 118 117 115 111 110 104 103 102 0.177 20d 145 137 132 131 128 124 123 116 115 113 0.192 20d 30d 150 141 136 135 132 128 127 120 118 116 1 0.099 5 6d 7d 62 58 55 55 53 51 51 47 47 46 0.113 5 6d 4 8d 8d 81 75 72 71 69 67 66 62 61 60 0.120 5 10d 92 85 81 81 78 76 75 69 69 67 0.128 10d 104 97 93 92 89 86 85 79 78 77 0.131 8d 109 101 97 96 93 90 89 83 82 80 0.135 16d 12d 116 108 103 102 99 96 94 88 87 85 0.148 10d 20d 16d 132 123 118 116 113 109 108 100 99 97 0.162 16d 40d 154 146 141 139 135 131 129 120 119 116 0.177 20d 169 160 155 154 151 146 145 137 136 134 0.192 20d 30d 174 164 159 158 155 150 149 141 140 138 1-1/8 0.128 5 10d 104 97 93 92 89 86 85 79 78 77 0.131 5 8d 109 101 97 96 93 90 89 83 82 80 0.135 5 16d 12d 116 108 103 102 99 96 94 88 87 85 0.148 5 10d 20d 16d 132 123 118 116 113 109 108 100 99 97 0.162 16d 40d 158 147 141 139 135 131 129 120 119 116 0.177 20d 181 170 163 161 157 151 149 139 137 135 0.192 20d 30d 186 176 170 168 163 157 155 145 143 140 1-1/4 0.148 10d 20d 16d 132 123 118 116 113 109 108 100 99 97 0.162 16d 40d 158 147 141 139 135 131 129 120 119 116 0.177 20d 183 170 163 161 157 151 149 139 137 135 0.192 20d 30d 191 177 170 168 163 157 155 145 143 140 1. Tabulated lateral design values, Z, shall be multiplied by all applicable adjustment factors (see Table 11.3.1). 2. Tabulated lateral design values, Z, are for common, box, or sinker steel wire nails (see Appendix Table L4) inserted in side grain with nail axis perpendicular to wood fibers; nail penetration, p, into the main member equal to 10D and nail bending yield strengths, F yb, of 100,000 psi for 0.099" D 0.142", 90,000 psi for 0.142" < D 0.177", 80,000 psi for 0.177" < D 0.236", and 70,000 psi for 0.236" < D 0.273". 3. Where the nail or spike penetration, p, is less than 10D but not less than 6D, tabulated lateral design values, Z, shall be multiplied by p/10d or lateral design values shall be calculated using the provisions of 12.3 for the reduced penetration. 4. Nail length is insufficient to provide 10D penetration. Tabulated lateral design values, Z, shall be adjusted per footnote 3. 5. Tabulated lateral design values, Z, shall be permitted to apply for greater side member thickness when adjusted per footnote 3. G=0.46 Douglas Fir(S) Hem-Fir(N) G=0.43 Hem-Fir G=0.42 Spruce-Pine-Fir G=0.37 Redwood (open grain) G=0.36 Eastern Softwoods Spruce-Pine-Fir(S) Western Cedars Western Woods G=0.35 Northern Species

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 113 Table 12R Side Member Thickness Nail Diameter Common Wire Nail COMMON, BOX, or SINKER STEEL WIRE NAILS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections 1,2,3 with wood structural panel side members with an effective G=0.42 (tabulated lateral design values are calculated based on an assumed nail penetration, p, into the main member equal to 10D) Box Nail Sinker Nail G=0.67 Red Oak G=0.55 Mixed Maple Southern Pine G=0.5 Douglas Fir-Larch G=0.49 Douglas Fir-Larch (N) 1. Tabulated lateral design values, Z, shall be multiplied by all applicable adjustment factors (see Table 11.3.1). 2. Tabulated lateral design values, Z, are for common, box, or sinker steel wire nails (see Appendix Table L4) inserted in side grain with nail axis perpendicular to wood fibers; nail penetration, p, into the main member equal to 10D and nail bending yield strengths, F yb, of 100,000 psi for 0.099" D 0.142", 90,000 psi for 0.142" < D 0.177", 80,000 psi for 0.177" < D 0.236", and 70,000 psi for 0.236" < D 0.273". 3. Where the nail or spike penetration, p, is less than 10D but not less than 6D, tabulated lateral design values, Z, shall be multiplied by p/10d or lateral design values shall be calculated using the provisions of 12.3 for the reduced penetration. 4. Nail length is insufficient to provide 10D penetration. Tabulated lateral design values, Z, shall be adjusted per footnote 3. 5. Tabulated lateral design values, Z, shall be permitted to apply for greater side member thickness when adjusted per footnote 3. G=0.46 Douglas Fir(S) Hem-Fir(N) G=0.43 Hem-Fir G=0.42 Spruce-Pine-Fir G=0.37 Redwood (open grain) G=0.36 Eastern Softwoods Spruce-Pine-Fir(S) Western Cedars Western Woods t s D in. in. Pennyweight lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. 3/8 0.099 6d 7d 41 39 37 37 36 35 35 33 33 32 0.113 6d 8d 8d 52 49 48 47 46 45 45 42 42 41 0.120 10d 58 55 53 53 52 50 50 47 47 46 0.128 10d 66 62 60 60 59 57 56 53 53 52 0.131 8d 69 65 63 63 61 59 59 56 55 54 0.135 16d 12d 73 69 67 66 65 63 62 59 58 57 0.148 10d 20d 16d 84 79 76 76 74 72 71 67 66 65 7/16 0.099 6d 7d 42 40 39 38 38 37 36 35 34 34 0.113 6d 8d 8d 53 50 49 48 48 46 46 43 43 42 0.120 10d 59 56 54 54 53 51 51 48 48 47 0.128 10d 67 63 61 61 60 58 57 54 54 53 0.131 8d 70 66 64 64 62 60 60 57 56 55 0.135 16d 12d 74 70 68 67 66 64 63 60 59 58 0.148 10d 20d 16d 84 80 77 76 75 73 72 68 67 66 0.162 16d 40d 100 95 92 91 89 86 85 81 80 78 15/32 0.099 6d 7d 43 41 40 39 39 38 37 35 35 35 0.113 6d 8d 8d 54 51 50 49 48 47 47 44 44 43 0.120 10d 60 57 55 55 54 52 52 49 49 48 0.128 10d 68 64 62 62 60 59 58 55 55 54 0.131 8d 70 67 65 64 63 61 61 57 57 56 0.135 16d 12d 75 71 68 68 66 65 64 61 60 59 0.148 10d 20d 16d 85 80 78 77 75 73 72 69 68 67 0.162 16d 40d 101 95 92 91 89 87 86 81 80 79 19/32 0.099 6d 7d 47 45 44 43 43 41 41 39 39 38 0.113 6d 8d 8d 58 55 54 53 52 51 50 48 48 47 0.120 10d 64 61 59 59 58 56 56 53 52 52 0.128 10d 71 68 66 65 64 62 62 59 58 57 0.131 8d 74 70 68 68 67 65 64 61 61 60 0.135 16d 12d 78 74 72 71 70 68 68 64 64 63 0.148 10d 20d 16d 88 84 81 81 79 77 76 72 72 71 0.162 16d 40d 103 98 95 94 93 90 89 85 84 83 0.177 20d 118 112 108 108 105 102 101 96 95 94 0.192 20d 30d 123 116 112 112 109 106 105 100 99 97 23/32 0.099 6d 7d 52 50 48 48 47 46 46 44 43 43 0.113 6d 8d 8d 63 60 58 58 57 56 55 53 52 52 0.120 10d 69 66 64 64 62 61 60 58 57 56 0.128 10d 76 73 71 70 69 67 67 63 63 62 0.131 8d 79 75 73 73 71 70 69 66 65 64 0.135 16d 12d 83 79 77 76 75 73 72 69 68 67 0.148 10d 20d 16d 93 89 86 86 84 82 81 77 77 76 0.162 16d 40d 108 103 100 99 98 95 94 90 89 87 0.177 20d 122 116 113 112 110 107 106 101 100 98 0.192 20d 30d 127 120 117 116 114 111 110 104 103 102 1 0.099 5 6d 7d 56 53 51 50 49 48 47 44 44 43 0.113 5 6d 4 8d 8d 73 68 66 66 64 62 61 58 57 56 0.120 5 10d 82 77 75 74 72 70 69 65 64 63 0.128 10d 91 87 85 84 82 80 79 74 73 72 0.131 8d 93 89 87 87 85 83 82 77 77 75 0.135 16d 12d 97 93 91 90 89 87 86 82 81 80 0.148 10d 20d 16d 109 104 101 101 99 97 96 91 91 90 0.162 16d 40d 124 118 115 115 113 110 109 104 103 102 0.177 20d 137 131 128 127 125 122 121 115 114 112 0.192 20d 30d 141 135 131 131 128 125 124 118 117 116 1-1/8 0.128 5 10d 93 88 85 84 82 80 79 74 73 72 0.131 5 8d 98 92 89 88 86 83 82 77 77 75 0.135 5 16d 12d 104 98 94 94 91 88 88 82 81 80 0.148 5 10d 20d 16d 117 111 108 107 104 101 100 94 93 91 0.162 16d 40d 132 127 123 123 120 118 117 111 110 109 0.177 20d 146 139 136 135 132 129 128 122 121 120 0.192 20d 30d 150 143 139 138 136 133 132 126 125 123 1-1/4 0.148 10d 20d 16d 118 111 108 107 104 101 100 94 93 91 0.162 16d 40d 141 134 129 128 125 121 120 112 111 109 0.177 20d 155 148 144 143 141 138 136 130 129 126 0.192 20d 30d 159 152 148 147 144 141 140 134 133 131 G=0.35 Northern Species NAILS DOWEL-TYPE FASTENERS 12

114 DOWEL-TYPE FASTENERS NAILS Table 12S POST FRAME RING SHANK NAILS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections 1,2,3 for sawn lumber or SCL with both members of identical specific gravity (tabulated lateral design values are calculated based on an assumed length of nail penetration, p, into the main member equal to 10D) Side Member Thickness Nail Diameter Nail Length G=0.67 Red Oak G=0.55 Mixed Maple Southern Pine G=0.5 Douglas Fir-Larch G=0.49 Douglas Fir-Larch (N) G=0.46 Douglas Fir(S) Hem-Fir(N) G=0.43 Hem-Fir G=0.42 Spruce-Pine-Fir G=0.37 Redwood (open grain) G=0.36 Eastern Softwoods Spruce-Pine-Fir (S) Western Cedars Western Woods G=0.35 Northern Species t s D L in. in. in. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. 1/2 0.135 3, 3.5 114 89 80 78 73 67 65 57 56 54 0.148 3-4.5 127 100 89 87 81 75 73 64 63 61 0.177 3-8 173 139 125 122 115 107 105 93 91 88 0.200 3.5-8 188 151 137 134 126 118 115 102 100 95 0.207 4-8 193 156 142 138 131 122 119 106 102 96 3/4 0.135 3, 3.5 138 106 93 90 83 75 73 62 61 58 0.148 3-4.5 156 118 103 100 92 84 81 70 68 65 0.177 3-8 204 157 139 134 125 115 112 97 94 91 0.200 3.5-8 218 168 149 145 135 124 121 105 103 99 0.207 4-8 223 173 153 149 139 128 125 109 106 103 1 0.135 3, 3.5 138 115 106 103 97 87 84 70 68 65 0.148 3-4.5 156 130 119 116 107 96 93 78 76 73 0.177 3-8 227 181 158 153 141 128 124 105 102 98 0.200 3.5-8 250 193 168 163 151 137 133 113 110 106 0.207 4-8 259 197 172 166 154 140 136 116 113 109 1 1/4 0.135 3, 3.5 138 115 106 103 98 92 90 80 77 74 0.148 3-4.5 156 130 119 116 110 103 101 88 86 82 0.177 3-8 227 189 173 170 160 143 139 116 112 107 0.200 3.5-8 250 208 191 184 169 152 147 123 120 115 0.207 4-8 259 216 195 188 172 155 150 126 123 118 1 1/2 0.135 3, 3.5 138 115 106 103 98 92 90 80 78 76 0.148 3-4.5 156 130 119 116 110 103 101 90 88 85 0.177 3-8 227 189 173 170 161 150 147 128 124 118 0.200 3.5-8 250 208 191 187 177 166 162 136 132 126 0.207 4-8 259 216 198 194 184 172 167 139 134 128 1 3/4 0.135 3, 3.5 138 115 106 103 98 92 90 80 78 76 0.148 3-4.5 156 130 119 116 110 103 101 90 88 85 0.177 3 4, 3.5 4,4-8 227 189 173 170 161 150 147 131 128 125 0.200 3.5 4, 4-8 250 208 191 187 177 166 162 144 141 137 0.207 4-8 259 216 198 194 184 172 168 149 147 140 2 1/2 0.135 3.5 4 138 115 106 103 98 92 90 80 78 76 0.148 3.5 4, 4, 4.5 156 130 119 116 110 103 101 90 88 85 0.177 4 4, 4.5, 5, 6, 8 227 189 173 170 161 150 147 131 128 125 0.200 4 4, 4.5, 5, 6, 8 250 208 191 187 177 166 162 144 141 137 0.207 4 4, 4.5 4, 5, 6, 8 259 216 198 194 184 172 168 149 147 142 3 1/2 0.148 4.5 4 156 130 119 116 110 103 101 90 88 85 0.177 5 4, 6, 8 227 189 173 170 161 150 147 131 128 125 0.200 5 4, 6, 8 250 208 191 187 177 166 162 144 141 137 0.207 5 4, 6, 8 259 216 198 194 184 172 168 149 147 142 1. Tabulated lateral design values, Z, shall be multiplied by all applicable adjustment factors (see Table 11.3.1). 2. Tabulated lateral design values, Z, are for post frame ring shank nails (see Appendix Table L5) inserted in side grain with nail axis perpendicular to wood fibers; nail penetration, p, into the main member equal to 10D; and nail bending yield strengths, F yb, of 130,000 psi for 0.120"< D 0.142", 115,000 psi for 0.142"< D 0.192", and 100,000 psi for 0.192"< D 0.207". 3. Where the post-frame ring shank nail penetration, p, is less than 10D but not less than 6D, tabulated lateral design values, Z, shall be multiplied by p/10d or lateral design values shall be calculated using the provisions of 12.3 for the reduced penetration. 4. Nail length is insufficient to provide 10D penetration. Tabulated lateral design values, Z, shall be adjusted per footnote 3.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 115 Table 12T POST FRAME RING SHANK NAILS: Reference Lateral Design Values, Z, for Single Shear (two member) Connections 1,2,3 for sawn lumber or SCL with ASTM A653, Grade 33 steel side plates (tabulated lateral design values are calculated based on an assumed nail penetration, p, into the main member equal to 10D) NAILS Side Member Thickness Nail Diameter Nail Length G=0.67 Red Oak G=0.55 Mixed Maple Southern Pine G=0.5 Douglas Fir-Larch G=0.49 Douglas Fir-Larch (N) G=0.46 Douglas Fir(S) Hem-Fir(N) G=0.43 Hem-Fir G=0.42 Spruce-Pine-Fir G=0.37 Redwood (open grain) G=0.36 Eastern Softwoods Spruce-Pine-Fir (S) Western Cedars Western Woods t s D L in. in. in. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. lbs. 0.036 0.135 3, 3.5 130 111 102 100 95 89 88 78 77 75 (20 gage) 0.148 3-4.5 142 125 115 113 107 101 99 88 87 84 0.177 3-8 171 171 167 164 156 146 143 128 126 122 0.200 3.5-8 177 177 177 177 172 161 158 141 139 135 0.207 4-8 178 178 178 178 178 167 164 146 144 140 0.048 0.135 3, 3.5 131 111 103 101 96 90 88 79 78 76 (18 gage) 0.148 3-4.5 147 125 116 113 108 101 99 89 87 85 0.177 3-8 213 182 168 164 156 147 144 129 127 123 0.200 3.5-8 235 200 184 181 172 162 158 142 139 135 0.207 4-8 237 207 191 187 178 168 164 147 144 140 0.060 0.135 3, 3.5 132 113 104 102 97 92 90 81 79 77 (16 gage) 0.148 3-4.5 148 126 117 115 109 103 101 90 89 86 0.177 3-8 214 183 169 165 157 148 145 130 128 124 0.200 3.5-8 235 201 185 182 173 163 159 143 140 136 0.207 4-8 244 208 192 188 179 168 165 148 145 141 0.075 0.135 3, 3.5 134 115 106 104 100 94 92 83 81 79 (14 gage) 0.148 3-4.5 150 129 119 117 112 105 103 93 91 88 0.177 3-8 216 185 171 167 160 150 147 132 130 126 0.200 3.5-8 237 203 187 183 175 164 161 145 142 138 0.207 4-8 246 210 194 190 181 170 167 150 147 143 0.105 0.135 3, 3.5 142 122 113 111 106 100 98 88 87 83 (12 gage) 0.148 3-4.5 159 137 127 124 119 112 110 99 97 94 0.177 3-8 223 192 178 174 166 157 154 138 136 132 0.200 3.5-8 244 209 194 190 181 171 167 150 148 144 0.207 4-8 252 216 200 196 187 176 173 155 153 148 0.120 0.135 3, 3.5 147 127 118 115 110 104 102 92 90 86 (11 gage) 0.148 3-4.5 164 141 131 129 123 116 114 103 101 98 0.177 3-8 228 197 182 179 171 161 158 142 140 136 0.200 3.5-8 249 214 198 194 185 175 171 154 152 147 0.207 4-8 257 221 204 200 191 180 177 159 156 152 0.134 0.135 3, 3.5 152 132 122 120 115 108 106 96 93 88 (10 gage) 0.148 3-4.5 169 147 136 134 128 120 118 107 105 102 0.177 3-8 234 202 187 184 175 165 162 146 144 140 0.200 3.5-8 254 219 203 199 190 179 176 158 156 151 0.207 4-8 262 225 209 205 196 185 181 163 160 156 0.179 0.135 3, 3.5 172 149 139 136 131 123 121 105 102 98 (7 gage) 0.148 3-4.5 191 166 154 151 145 137 134 121 118 113 0.177 3-8 256 222 206 202 193 183 179 162 159 153 0.200 3.5-8 276 238 221 217 208 196 192 174 171 166 0.207 4-8 283 245 227 223 213 201 197 178 175 170 0.239 0.135 3, 3.5 184 156 144 141 134 126 124 106 102 98 (3 gage) 0.148 3-4.5 207 176 162 159 151 142 139 124 120 114 0.177 3-8 293 255 236 232 220 207 203 179 174 165 0.200 3.5-8 312 271 252 248 237 224 220 199 195 189 0.207 4-8 319 277 258 253 242 229 224 203 199 194 1. Tabulated lateral design values, Z, shall be multiplied by all applicable adjustment factors (see Table 11.3.1). 2. Tabulated lateral design values, Z, are for post frame ring shank nails (see Appendix Table L5) inserted in side grain with nail axis perpendicular to wood fibers; nail penetration, p, into the main member equal to 10D; and nail bending yield strengths, F yb, of 130,000 psi for 0.120"< D 0.142" 115,000 psi for 0.142"< D 0.192", and 100,000 psi for 0.192"< D 0.207". 3. Where the post-frame ring shank nail penetration, p, is less than 10D but not less than 6D, tabulated lateral design values, Z, shall be multiplied by p/10d or lateral design values shall be calculated using the provisions of 12.3 for the reduced penetration. G=0.35 Northern Species DOWEL-TYPE FASTENERS 12

116 DOWEL-TYPE FASTENERS

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 117 SPLIT RING AND SHEAR PLATE CONNECTORS 13.1 General 118 13.2 Reference Design Values 119 13.3 Placement of Split Ring and Shear Plate Connectors 125 Table 13A Species Groups for Split Ring and Shear Plate Connectors...119 Table 13.2A Split Ring Connector Unit Reference Design Values...120 Table 13.2B Shear Plate Connector Unit Reference Design Values...121 Table 13.2.3 Penetration Depth Factors, C d, for Split Ring and Shear Plate Connectors Used with Lag Screws...122 Table 13.2.4 Metal Side Plate Factors, C st, for 4" Shear Plate Connectors Loaded Parallel to Grain...122 Table 13.3.2.2 Factors for Determining Minimum Spacing Along Connector Axis for C = 1.0...126 Table 13.3.3.1-1 Factors for Determining Minimum Spacing Along Axis of Cut of Sloping Surfaces...127 Table 13.3.3.1-2 Factors for Determining Minimum Loaded Edge Distance for Connectors in End Grain...127 Table 13.3.3.1-3 Factors for Determining Minimum Unloaded Edge Distance Parallel to Axis of Cut...128 Table 13.3.3.1-4 Factors for Determining Minimum End Distance Parallel to Axis of Cut...128 Table 13.3 Geometry Factors, C, for Split Ring and Shear Plate Connectors...129 13

118 SPLIT RING AND SHEAR PLATE CONNECTORS 13.1 General 13.1.1 Scope Chapter 13 applies to the engineering design of connections using split ring connectors or shear plate connectors in sawn lumber, structural glued laminated timber, and structural composite lumber. Design of split ring and shear plate connections in cross-laminated timber is beyond the scope of these provisions. 13.1.2 Terminology Figure 13C Malleable Iron Shear Plate Connector A connector unit shall be defined as one of the following: (a) One split ring with its bolt or lag screw in single shear (see Figure 13A). (b) Two shear plates used back to back in the contact faces of a wood-to-wood connection with their bolt or lag screw in single shear (see Figures 13B and 13C). (c) One shear plate with its bolt or lag screw in single shear used in conjunction with a steel strap or shape in a wood-to-metal connection (see Figures 13B and 13C). Figure 13A Figure 13B Split Ring Connector Pressed Steel Shear Plate Connector 13.1.3 Quality of Split Ring and Shear Plate Connectors 13.1.3.1 Design provisions and reference design values herein apply to split ring and shear plate connectors of the following quality: (a) Split rings manufactured from SAE 1010 hot rolled carbon steel (Reference 37). Each ring shall form a closed true circle with the principal axis of the cross section of the ring metal parallel to the geometric axis of the ring. The ring shall fit snugly in the precut groove. This shall be accomplished with a ring, the metal section of which is beveled from the central portion toward the edges to a thickness less than at midsection, or by any other method which will accomplish equivalent performance. It shall be cut through in one place in its circumference to form a tongue and slot (see Figure 13A). (b) Shear plate connectors: (1) 2-5/8" Pressed Steel Type Pressed steel shear plates manufactured from SAE 1010 (Reference 37) hot rolled carbon steel. Each plate shall be a true circle with a flange around the edge, extending at right angles to the face of the plate and extending from one face only, the plate portion having a central bolt hole, with an integral hub concentric to the hole or without an integral hub, and two small perforations on opposite sides of the hole and midway from the center and circumference (see Figure 13B). (2) 4" Malleable Iron Type Malleable iron shear plates manufactured according to Grade 32510 of ASTM Standard A47 (Reference 11). Each casting shall consist of a perforated round plate with a flange around

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 119 the edge extending at right angles to the face of the plate and projecting from one face only, the plate portion having a central bolt hole with an integral hub extending from the same face as the flange (see Figure 13C). 13.1.3.2 Dimensions for typical split ring and shear plate connectors are provided in Appendix K. Dimensional tolerances of split ring and shear plate connectors shall not be greater than those conforming to standard practices for the machine operations involved in manufacturing the connectors. 13.1.3.3 Bolts used with split ring and shear plate connectors shall conform to 12.1.3. The bolt shall have an unreduced nominal or shank (body) diameter in accordance with ANSI/ASME Standard B18.2.1 (Reference 7). 13.1.3.4 Where lag screws are used in place of bolts, the lag screws shall conform to 12.1.3 and the shank of the lag screw shall have the same diameter as the bolt specified for the split ring or shear plate connector (see Tables 13.2A and 13.2B). The lag screw shall have an unreduced nominal or shank (body) diameter and threads in accordance with ANSI/ASME Standard B18.2.1 (see Reference 7). 13.1.4 Fabrication and Assembly 13.1.4.1 The grooves, daps, and bolt holes specified in Appendix K shall be accurately cut or bored and shall be oriented in contacting faces. Since split ring and shear plate connectors from different manufacturers differ slightly in shape and cross section, cutter heads 13.2 Reference Design Values 13.2.1 Reference Design Values 13.2.1.1 Tables 13.2A and 13.2B contain reference design values for a single split ring or shear plate connector unit with bolt in single shear, installed in the side grain of two wood members (Table 13A) with sufficient member thicknesses, edge distances, end distances, and spacing to develop reference design values. Reference design values (P, Q) shall be multiplied by all applicable adjustment factors (see Table 11.3.1) to obtain adjusted design values (P', Q'). 13.2.1.2 Adjusted design values (P', Q') for shear plate connectors shall not exceed the limiting reference design values specified in Footnote 2 of Table 13.2B. shall be designed to produce daps and grooves conforming accurately to the dimensions and shape of the particular split ring or shear plate connectors used. 13.1.4.2 Where lag screws are used in place of bolts, the hole for the unthreaded shank shall be the same diameter as the shank. The diameter of the hole for the threaded portion of the lag screw shall be approximately 70% of the shank diameter, or as specified in 12.1.4.2. 13.1.4.3 In installation of split ring or shear plate connectors and bolts or lag screws, a nut shall be placed on each bolt, and washers, not smaller than the size specified in Appendix K, shall be placed between the outside wood member and the bolt or lag screw head and between the outside wood member and nut. Where an outside member of a shear plate connection is a steel strap or shape, the washer is not required, except where a longer bolt or lag screw is used, in which case, the washer prevents the metal plate or shape from bearing on the threaded portion of the bolt or lag screw. 13.1.4.4 Reference design values for split ring and shear plate connectors are based on the assumption that the faces of the members are brought into contact when the connector units are installed, and allow for seasonal variations after the wood has reached the moisture content normal to the conditions of service. Where split ring or shear plate connectors are installed in wood which is not seasoned to the moisture content normal to the conditions of service, the connections shall be tightened by turning down the nuts periodically until moisture equilibrium is reached. The limiting reference design values in Footnote 2 of Table 13.2B shall not be multiplied by adjustment factors in this Specification since they are based on strength of metal rather than strength of wood (see 11.2.3). Table 13A Species Groups for Split Ring and Shear Plate Connectors Species Group Specific Gravity, G A G 0.60 B 0.49 G < 0.60 C 0.42 G < 0.49 D G < 0.42 SPLIT RING AND SHEAR PLATE CONNECTORS 13

120 SPLIT RING AND SHEAR PLATE CONNECTORS Table 13.2A Split Ring Connector Unit Reference Design Values Tabulated design values 1 apply to ONE split ring and bolt in single shear. Split Bolt Number of faces Net Loaded parallel to grain (0 ) Loaded perpendicular to grain (90 ) ring diameter of member with thickness Design value, P, per connector unit Design value, Q, per connector unit diameter connectors on of member and bolt, lbs. and bolt, lbs. same bolt Group Group Group Group Group Group Group Group A B C D A B C D in. in. in. species species species species species species species species 1" 2630 2270 1900 1640 1900 1620 1350 1160 2-1/2 1/2 4 3/4 1 2 minimum 1-1/2" or 3160 2730 2290 1960 2280 1940 1620 1390 thicker 1-1/2" 2430 2100 1760 1510 1750 1500 1250 1070 minimum 2" or 3160 2730 2290 1960 2280 1940 1620 1390 thicker 1" 4090 3510 2920 2520 2840 2440 2040 1760 minimum 1 1-1/2" 6020 5160 4280 3710 4180 3590 2990 2580 1-5/8" or 6140 5260 4380 3790 4270 3660 3050 2630 thicker 2 1-1/2" 4110 3520 2940 2540 2980 2450 2040 1760 minimum 2" 4950 4250 3540 3050 3440 2960 2460 2120 2-1/2" 5830 5000 4160 3600 4050 3480 2890 2500 3" or 6140 5260 4380 3790 4270 3660 3050 2630 thicker 1. Tabulated lateral design values (P,Q) for split ring connector units shall be multiplied to all applicable adjustment factors (see Table 11.3.1).

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 121 Table 13.2B Shear Plate Connector Unit Reference Design Values Tabulated design values 1,2,3 apply to ONE shear plate and bolt in single shear. Shear Bolt Number of faces Net Loaded parallel to grain (0 ) Loaded perpendicular to grain (90 ) plate diameter of member with thickness Design value, P, per connector unit Design value, Q, per connector unit diameter connectors on of member and bolt, lbs. and bolt, lbs. same bolt Group Group Group Group Group Group Group Group A B C D A B C D in. in. in. species species species species species species species species 1-1/2" 3110* 2670 2220 2010 2170 1860 1550 1330 minimum 1-1/2" 2420 2080 1730 1500 1690 1450 1210 1040 1 2-5/8 3/4 minimum 2 2" 3190* 2730 2270 1960 2220 1910 1580 1370 2-1/2" or 3330* 2860 2380 2060 2320 1990 1650 1440 thicker 1-1/2" 4370 3750 3130 2700 3040 2620 2170 1860 minimum 1-3/4" or 5090* 4360 3640 3140 3540 3040 2530 2200 1 3/4 thicker 1-3/4" 3390 2910 2420 2090 2360 2020 1680 1410 4 or minimum 2" 3790 3240 2700 2330 2640 2260 1880 1630 7/8 2 2-1/2" 4310 3690 3080 2660 3000 2550 2140 1850 3" 4830* 4140 3450 2980 3360 2880 2400 2060 3-1/2" or 5030* 4320 3600 3110 3500 3000 2510 2160 thicker 1. Tabulated lateral design values (P,Q) for shear plate connector units shall be multiplied to all applicable adjustment factors (see Table 11.3.1). 2. Allowable design values for shear plate connector units shall not exceed the following: (a) 2-5/8" shear plate... 2900 pounds (b) 4" shear plate with 3/4" bolt... 4400 pounds (c) 4" shear plate with 7/8" bolt... 6000 pounds The design values in Footnote 2 shall be permitted to be increased in accordance with the American Institute of Steel Construction (AISC) Manual of Steel Construction, 9th edition, Section A5.2 Wind and Seismic Stresses, except when design loads have already been reduced by load combination factors (see 11.2.3). 3. Loads followed by an asterisk (*) exceed those permitted by Footnote 2, but are needed for determination of design values for other angles of load to grain. Footnote 2 limitations apply in all cases. SPLIT RING AND SHEAR PLATE CONNECTORS 13

122 SPLIT RING AND SHEAR PLATE CONNECTORS 13.2.2 Thickness of Wood Members 13.2.2.1 Reference design values shall not be used for split ring or shear plate connectors installed in any piece of wood of a net thickness less than the minimum specified in Tables 13.2A and 13.2B. 13.2.2.2 Reference design values for split ring or shear plate connectors installed in any piece of wood of net thickness intermediate between the minimum thickness and that required for maximum reference design value, as specified in Tables 13.2A and 13.2B, shall be obtained by linear interpolation. 13.2.3 Penetration Depth Factor, Cd Where lag screws instead of bolts are used with split ring or shear plate connectors, reference design values shall be multiplied by the appropriate penetration depth factor, C d, specified in Table 13.2.3. Lag screw penetration into the member receiving the point shall not be less than the minimum penetration specified in Table 13.2.3. Where the actual lag screw penetration into the member receiving the point is greater than the minimum penetration, but less than the minimum penetration for C d = 1.0, the penetration depth factor, C d, shall be determined by linear interpolation. The penetration depth factor shall not exceed unity, C d 1.0. 13.2.4 Metal Side Plate Factor, Cst Where metal side members are used in place of wood side members, the reference design values parallel to grain, P, for 4" shear plate connectors shall be multiplied by the appropriate metal side plate factor specified in Table 13.2.4. Table 13.2.4 Metal Side Plate Factors, Cst, for 4" Shear Plate Connectors Loaded Parallel to Grain Species Group C st A 1.18 B 1.11 C 1.05 D 1.00 The adjusted design values parallel to grain, P', shall not exceed the limiting reference design values given in Footnote 2 of Table 13.2B (see 13.2.1.2). 13.2.5 Load at Angle to Grain 13.2.5.1 Where a load acts in the plane of the wood surface at an angle to grain other than 0 or 90, the adjusted design value, N', for a split ring or shear plate connector unit shall be determined as follows (see Appendix J): where: PQ N (13.2-1) Psin 2 Qcos 2 = angle between direction of load and direction of grain (longitudinal axis of member), degrees 13.2.5.2 Adjusted design values at an angle to grain, N', for shear plate connectors shall not exceed the limiting reference design values specified in Footnote 2 of Table 13.2.B (see 13.2.1.2). Table 13.2.3 2-1/2" Split Ring 4" Split Ring 4" Shear Plate 2-5/8" Shear Plate Penetration Depth Factors, Cd, for Split Ring and Shear Plate Connectors Used with Lag Screws Side Member Wood or Metal Wood Metal Penetration Minimum for C d = 1.0 Minimum for C d = 0.75 Minimum for C d = 1.0 Minimum for C d = 0.75 Minimum for C d = 1.0 Penetration of Lag Screw into Main Member (number of shank diameters) Species Group (see Table 13A) Group A Group B Group C Group D Penetration Depth Factor, C d 7 8 10 11 1.0 3 3-1/2 4 4-1/2 0.75 4 5 7 8 1.0 3 3-1/2 4 4-1/2 0.75 3 3-1/2 4 4-1/2 1.0

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 123 13.2.6 Split Ring and Shear Plate Connectors in End Grain 13.2.6.1 Where split ring or shear plate connectors are installed in a surface that is not parallel to the general direction of the grain of the member, such as the end of a square-cut member, or the sloping surface of a member cut at an angle to its axis, or the surface of a structural glued laminated timber cut at an angle to the direction of the laminations, the following terminology shall apply: - Side grain surface means a surface parallel to the general direction of the wood fibers ( = 0 ), such as the top, bottom, and sides of a straight beam. - Sloping surface means a surface cut at an angle,, other than 0 or 90 to the general direction of the wood fibers. - Square-cut surface means a surface perpendicular to the general direction of the wood fibers ( = 90 ). - Axis of cut defines the direction of a sloping surface relative to the general direction of the wood fibers. For a sloping cut symmetrical about one of the major axes of the member, as in Figures 13D, 13G, 13H, and 13I, the axis of cut is parallel to a major axis. For an asymmetrical sloping surface (i.e., one that slopes relative to both major axes of the member), the axis of cut is the direction of a line defining the intersection of the sloping surface with any plane that is both normal to the sloping surface and also is aligned with the general direction of the wood fibers (see Figure 13E). = the least angle formed between a sloping surface and the general direction of the wood fibers (i.e., the acute angle between the axis of cut and the general direction of the fibers. Sometimes called the slope of the cut. See Figures 13D through 13I). Q'90 = adjusted design value for a split ring or shear plate connector unit in a square-cut surface, loaded in any direction in the plane of the surface ( = 90). Figure 13D Figure 13E P' = adjusted design value for a split ring or shear plate connector unit in a sloping surface, loaded in a direction parallel to the axis of cut (0 < < 90, = 0). Q' = adjusted design value for a split ring or shear plate connector unit in a sloping surface, loaded in a direction perpendicular to the axis of cut (0 < < 90, = 90). N' = adjusted design value for a split ring or shear plate connector unit in a sloping surface, where direction of load is at an angle from the axis of cut. Axis of Cut for Symmetrical Sloping End Cut Axis of Cut for Asymmetrical Sloping End Cut SPLIT RING AND SHEAR PLATE CONNECTORS = the angle between the direction of applied load and the axis of cut of a sloping surface, measured in the plane of the sloping surface (see Figure 13I). 13 P' = adjusted design value for a split ring or shear plate connector unit in a side grain surface, loaded parallel to grain ( = 0, = 0). Q' = adjusted design value for a split ring or shear plate connector unit in a side grain surface, loaded perpendicular to grain ( = 0, = 90).

124 SPLIT RING AND SHEAR PLATE CONNECTORS 13.2.6.2 Where split ring or shear plate connectors are installed in square-cut end grain or sloping surfaces, adjusted design values shall be determined as follows (see 11.2.2): (a) Square-cut surface; loaded in any direction ( = 90, see Figure 13F). Q90 = 0.60Q (13.2-2) Figure 13F Square End Cut (c) Sloping surface; loaded perpendicular to axis of cut (0 < < 90, = 90, see Figure 13H). Q QQ 90 2 2 Q sin Q90 cos Figure 13H Sloping End Cut with Load Perpendicular to Axis of Cut ( = 90) (13.2-4) (b) Sloping surface; loaded parallel to axis of cut (0 < < 90, = 0, see Figure 13G). P PQ 90 2 2 P sin Q90 cos (13.2-3) (d) Sloping surface; loaded at angle to axis of cut (0 < < 90, 0 < < 90, see Figure 13I). N P Q P sin 2 Q cos 2 (13.2-5) Figure 13G Sloping End Cut with Load Parallel to Axis of Cut ( = 0) Figure 13 Sloping End Cut with Load at an Angle to Axis of Cut

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 125 13.3 Placement of Split Ring and Shear Plate Connectors 13.3.1 Terminology 13.3.1.1 Edge distance is the distance from the edge of a member to the center of the nearest split ring or shear plate connector, measured perpendicular to grain. Where a member is loaded perpendicular to grain, the loaded edge shall be defined as the edge toward which the load is acting. The unloaded edge shall be defined as the edge opposite the loaded edge (see Figure 13J). 13.3.1.2 End distance is the distance measured parallel to grain from the square-cut end of a member to the center of the nearest split ring or shear plate connector (see Figure 13J). If the end of a member is not cut at a right angle to its longitudinal axis, the end distance, measured parallel to the longitudinal axis from any point on the center half of the transverse connector diameter, shall not be less than the end distance required for a square-cut member. In no case shall the perpendicular distance from the center of a connector to the sloping end cut of a member, be less than the required edge distance (see Figure 13K). Figure 13J Connection Geometry for Split Rings and Shear Plates 13.3.1.3 Connector axis is a line joining the centers of any two adjacent connectors located in the same face of a member (see Figure 13L). 13.3.1.4 Spacing is the distance between centers of split ring or shear plate connectors measured along their connector axis (see Figure 13J). Figure 13K Figure 13L End Distance for Members with Sloping End Cut Connector Axis and Load Angle Connector Axis 13.3.2 Geometry Factor, C, for Split Ring and Shear Plate Connectors in Side Grain Reference design values are for split ring and shear plate connectors installed in side grain with edge distance, end distance, and spacing greater than or equal to the minimum required for C = 1.0. Where the edge distance, end distance, or spacing provided is less than the minimum required for C = 1.0, reference design values shall be multiplied by the smallest applicable geometry factor, C, determined from the edge distance, end distance, and spacing requirements for split ring and shear plate connectors. The smallest geometry factor for any split ring or shear plate connector in a group shall apply to all split ring and shear plate connectors in the group. Edge distance, end distance, and spacing shall not be less than the minimum values specified in 13.3.2.1 and 13.3.2.2. P SPLIT RING AND SHEAR PLATE CONNECTORS 13

126 SPLIT RING AND SHEAR PLATE CONNECTORS 13.3.2.1 Connectors Loaded Parallel or Perpendicular to Grain. For split ring and shear plate connectors loaded parallel or perpendicular to grain, minimum values for edge distance, end distance, and spacing are provided in Table 13.3 with their associated geometry factors, C. Where the actual value is greater than or equal to the minimum value, but less than the minimum value for C = 1.0, the geometry factor, C, shall be determined by linear interpolation. 13.3.2.2. Connectors Loaded at an Angle to Grain. For split rings and shear plate connectors where the angle between the direction of load and the direction of grain,, is other than 0 or 90, separate geometry factors for edge distance and end distance shall be determined for the parallel and perpendicular to grain components of the resistance. For split ring and shear plate connectors loaded at an angle to grain,, other than 0 or 90, the minimum spacing for C = 1.0 shall be determined in accordance with Equation 13.3-1. where: SS A B S 2 2 2 2 S sin S cos A B S = minimum spacing along connector axis SA = factor from Table 13.3.2.2 SB = factor from Table 13.3.2.2 = angle of connector axis to the grain Table 13.3.2.2 Connector 2-1/2" split ring or 2-5/8" shear plate 4" split ring or 4" shear plate (13.3-1) Factors for Determining Minimum Spacing Along Connector Axis for C = 1.0 Angle of Load to S A S B Grain 1 (degrees) in. in. 0 6.75 3.50 15 6.00 3.75 30 5.13 3.88 45 4.25 4.13 60-90 3.5 4.25 0 9.00 5.00 15 8.00 5.25 30 7.00 5.50 45 6.00 5.75 60-90 5.00 6.00 1. Interpolation shall be permitted for intermediate angles of load to grain. The minimum spacing shall be 3.50" for 2-1/2" split rings and 2-5/8" shear plates and shall be 5.0" for 4" split ring or shear plate connectors. For this minimum spacing, C = 0.5. Where the actual spacing between split ring or shear plate connectors is greater than the minimum spacing but less than the minimum spacing for C = 1.0, the geometry factor, C, shall be determined by linear interpolation. The geometry factor calculated for spacing shall be applied to reference design values for both parallel and perpendicular-to-grain components of the resistance. 13.3.3 Geometry Factor, C, for Split Ring and Shear Plate Connectors in End Grain For split ring and shear plate connectors installed in end grain, a single geometry factor shall be determined and applied to reference design values for both parallel and perpendicular to grain components of the resistance. Edge distance, end distance, and spacing shall not be less than the minimum values specified in 13.3.3.1 and 13.3.3.2. 13.3.3.1 The provisions for geometry factors, C, for split ring and shear plate connectors installed in square-cut surfaces and sloping surfaces shall be as follows (see 13.2.6 for definitions and terminology): (a) Square-cut surface, loaded in any direction (see Figure 13F) - provisions for perpendicular to grain loading for connectors installed in side grain shall apply except for end distance provisions. (b) Sloping surface loaded parallel to axis of cut (see Figure 13G). (b.1) Spacing. The minimum spacing parallel to the axis of cut for C = 1.0 shall be determined in accordance with Equation 13.3-2. The minimum spacing parallel to the axis of cut shall be 3.5" for 2-1/2" split rings and 2-5/8" shear plates and shall be 5.0" for 4" split ring or shear plate connectors. For this minimum spacing, C = 0.5. Where the actual spacing parallel to the axis of cut between split ring or shear plate connectors is greater than the minimum spacing for C = 0.5, but less than the minimum spacing for C = 1.0, the geometry factor, C shall be determined by linear interpolation.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 127 S α SS S sin α S cos α 2 2 2 2 (13.3-2) E α EE E sin α E cos α 2 2 2 2 (13.3-3) where: S = minimum spacing parallel to axis of cut SII = factor from Table 13.3.3.1-1 S = factor from Table 13.3.3.1-1 = angle of sloped cut (see Figure 13G) Table 13.3.3.1-1 Factors for Determining Minimum Spacing Along Axis of Cut of Sloping Surfaces Connector 2-1/2" split ring or 2-5/8" shear plate 4" split ring or 4" shear plate Geometry Factor S II in. S in. C = 1.0 6.75 4.25 C = 1.0 9.00 6.00 (b.2) Loaded Edge Distance. The minimum loaded edge distance parallel to the axis of cut for C = 1.0 shall be determined in accordance with Equation 13.3-3. For split rings, the minimum loaded edge distance parallel to the axis of cut for C = 0.70 shall be determined in accordance with Equation 13.3-3. For shear plates, the minimum loaded edge distance parallel to the axis of cut for C = 0.83 shall be determined in accordance with Equation 13.3-3. Where the actual loaded edge distance parallel to the axis of cut is greater than the minimum loaded edge distance parallel to the axis of cut for C = 0.70 for split rings or for C = 0.83 for shear plates, but less than the minimum loaded edge distance parallel to the axis of cut for C = 1.0, the geometry factor, C, shall be determined by linear interpolation. where: E = minimum loaded edge distance parallel to axis of cut EII = factor from Table 13.3.3.1-2 E = factor from Table 13.3.3.1-2 = angle of sloped cut (see Figure 13G) Table 13.3.3.1-2 Factors for Determining Minimum Loaded Edge Distance for Connectors in End Grain Connector 2-1/2" split ring 2-5/8" shear plate 4" split ring 4" shear plate Geometry Factor E II in. E in. C = 1.00 5.50 2.75 C = 0.70 3.30 1.50 C = 1.00 5.50 2.75 C = 0.83 4.25 1.50 C = 1.00 7.00 3.75 C = 0.70 4.20 2.50 C = 1.00 7.00 3.75 C = 0.83 5.40 2.50 (b.3) Unloaded Edge Distance. The minimum unloaded edge distance parallel to the axis of cut for C = 1.0, shall be determined in accordance with Equation 13.3-4. The minimum unloaded edge distance parallel to the axis of cut for C = 0.63 shall be determined in accordance with Equation 13.3-4. Where the actual unloaded edge distance parallel to the axis of cut is greater than the minimum unloaded edge distance for C = 0.63, but less than the minimum unloaded edge distance for C = 1.0, the geometry factor, C, shall be determined by linear interpolation. SPLIT RING AND SHEAR PLATE CONNECTORS 13

128 SPLIT RING AND SHEAR PLATE CONNECTORS U α where: UU U sin α U cos α 2 2 2 2 (13.3-4) U = minimum unloaded edge distance parallel to axis of cut UII = factor from Table 13.3.3.1-3 U = factor from Table 13.3.3.1-3 α = angle of sloped cut (see Figure 13G) Table 13.3.3.1-3 Factors for Determining Minimum Unloaded Edge Distance Parallel to Axis of Cut Connector Geometry Factor U II in. U in. 2-1/2" split ring or C = 1.00 4.00 1.75 2-5/8" shear plate C = 0.63 2.50 1.50 4" split ring or 4" shear plate C = 1.00 5.50 2.75 C = 0.63 3.25 2.50 (b.4) Geometry factors for unloaded edge distance perpendicular to the axis of cut and for spacing perpendicular to the axis of cut shall be determined following the provisions for unloaded edge distance and perpendicular-to-grain spacing for connectors installed in side grain and loaded parallel to grain. (c) Sloping surface loaded perpendicular to axis of cut (see Figure 13H) - provisions for perpendicular to grain loading for connectors installed in end grain shall apply, except that: (1) The minimum end distance parallel to the axis of cut for C = 1.0 shall be determined in accordance with Equation 13.3-5. (2) The minimum end distance parallel to the axis of cut for C = 0.63 shall be determined in accordance with Equation 13.3-5. (3) Where the actual end distance parallel to the axis of cut is greater than the minimum end distance for C = 0.63, but less than the minimum unloaded edge distance for C = 1.0, the geometry factor, C, shall be determined by linear interpolation. e α where: EU 2 2 2 2 E sin α U cos α (13.3-5) e = minimum end distance parallel to axis of cut EII = factor from Table 13.3.3.1-4 U = factor from Table 13.3.3.1-4 α = angle of sloped cut (see Figure 13G) Table 13.3.3.1-4 Factors for Determining Minimum End Distance Parallel to Axis of Cut Connector Geometry Factor E II in. U in. 2-1/2" split ring or C = 1.00 5.50 1.75 2-5/8" shear plate C = 0.63 2.75 1.50 4" split ring or 4" shear plate C = 1.00 7.00 2.75 C = 0.63 3.50 2.50 (d) Sloping surface loaded at angle to axis of cut (see Figure 13I) - separate geometry factors, C, shall be determined for the components of resistance parallel and perpendicular to the axis of cut prior to applying Equation 13.2-5. 13.3.3.2 Where split ring or shear plate connectors are installed in end grain, the members shall be designed for shear parallel to grain in accordance with 3.4.3.3. 13.3.4 Multiple Split Ring or Shear Plate Connectors 13.3.4.1 Where a connection contains two or more split ring or shear plate connector units which are in the same shear plane, are aligned in the direction of load, and on separate bolts or lag screws, the group action factor, C g, shall be as specified in 11.3.6 and the total adjusted design value for the connection shall be as specified in 11.2.2. 13.3.4.2 If grooves for two sizes of split rings are cut concentric in the same wood surface, split ring connectors shall be installed in both grooves and the reference design value shall be taken as the reference design value for the larger split ring connector. 13.3.4.3 Local stresses in connections using multiple fasteners shall be evaluated in accordance with principles of engineering mechanics (see 11.1.2).

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 129 Table 13.3 Geometry Factors, C, for Split Ring and Shear Plate Connectors 4" Split Ring Connectors & 4" Shear Plate Connectors 2-1/2" Split Ring Connectors & 2-5/8" Shear Plate Connectors Perpendicular to grain loading Parallel to grain loading Perpendicular to grain loading Parallel to grain loading Minimum for C = 1.0 Minimum Value Minimum for C = 1.0 Minimum Value Minimum for C = 1.0 Minimum Value Minimum for C = 1.0 Minimum Value Unloaded Edge 1-1/2" 1-3/4" 1-1/2" 1-3/4" 2-1/2" 2-3/4" 2-1/2" 2-3/4" Edge Distance C 0.88 1.0 0.88 1.0 0.93 1.0 0.93 1.0 Loaded Edge 1-1/2" 2-3/4" 2-1/2" 3-3/4" 0.70 1.0 0.70 1.0 C for Split Rings 0.83 1.0 0.83 1.0 C for Shear Plates 2-3/4" 5-1/2" 2-3/4" 5-1/2" 3-1/2" 7" 3-1/2" 7" Tension Member End Distance C 0.63 1.0 0.63 1.0 0.63 1.0 0.63 1.0 2-1/2" 4" 2-3/4" 5-1/2" 3-1/4" 5-1/2" 3-1/2" 7" Compression Member C 0.63 1.0 0.63 1.0 0.63 1.0 0.63 1.0 3-1/2" 6-3/4" 3-1/2" 3-1/2" 5" 9" 5" 5" Spacing parallel to grain Spacing C 0.5 1.0 1.0 1.0 0.5 1.0 1.0 1.0 3-1/2" 3-1/2" 3-1/2" 4-1/4" 5" 5" 5" 6" Spacing perpendicular to grain C 1.0 1.0 0.5 1.0 1.0 1.0 0.5 1.0 SPLIT RING AND SHEAR PLATE CONNECTORS 13

130 SPLIT RING AND SHEAR PLATE CONNECTORS

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 131 TIMBER RIVETS 14.1 General 132 14.2 Reference Design Values 132 14.3 Placement of Timber Rivets 134 Table 14.2.3 Table 14.3.2 Metal Side Plate Factor, C st, for Timber Rivet Connections... 133 Minimum End and Edge Distances for Timber Rivet Joints... 134 Tables 14.2.1 A-F Reference Wood Capacity Design Values Parallel to Grain, P w, for Timber Rivets... 135 A - Rivet Length = 1-½", s p = 1", s q = 1"... 135 B - Rivet Length = 1-½", s p = 1-½", s q = 1"... 136 C - Rivet Length = 2-½", s p = 1", s q = 1"... 137 D - Rivet Length = 2-½", s p = 1-½", s q = 1"... 138 E - Rivet Length = 3-½", s p = 1", s q = 1"... 139 F - Rivet Length = 3-½", s p = 1-½", s q = 1"... 140 Table 14.2.2A Values of q w (lbs) Perpendicular to Grain for Timber Rivets... 141 Table 14.2.2B Geometry Factor, C, for Timber Rivet Connections Loaded Perpendicular to Grain... 141 14

132 TIMBER RIVETS 14.1 General 14.1.1 Scope Chapter 14 applies to the engineering design of timber rivet connections with steel side plates on Douglas Fir-Larch or Southern Pine structural glued laminated timber complying with Chapter 5 and loaded in single shear. Design of timber rivet connections in crosslaminated timber is beyond the scope of these provisions. 14.1.2 Quality of Rivets and Steel Side Plates 14.1.2.1 Design provisions and reference design values herein apply to timber rivets that are hot-dip galvanized in accordance with ASTM A 153 and manufactured from AISI 1035 steel to have the following properties tested in accordance with ASTM A 370: Hardness Rockwell C32-39 Ultimate tensile strength, F u 145,000 psi, minimum See Appendix M for rivet dimensions. 14.1.2.2 Steel side plates shall conform to ASTM Standard A 36 with a minimum 1/8" thickness. See Appendix M for steel side plate dimensions. 14.1.2.3 For wet service conditions, steel side plates shall be hot-dip galvanized in accordance with ASTM A 153. 14.1.3 Fabrication and Assembly 14.1.3.1 Each rivet shall, in all cases, be placed with its major cross-sectional dimension aligned parallel to the grain. Design criteria are based on rivets driven through circular holes in the side plates until the conical heads are firmly seated, but rivets shall not be driven flush. (Timber rivets at the perimeter of the group shall be driven first. Successive timber rivets shall be driven in a spiral pattern from the outside to the center of the group.) 14.1.3.2 The maximum penetration of any rivet shall be 70% of the thickness of the wood member. Except as permitted by 14.1.3.3, for joints with rivets driven from opposite faces of a wood member, the rivet length shall be such that the points do not overlap. 14.1.3.3 For joints where rivets are driven from opposite faces of a wood member such that their points overlap, the minimum spacing requirements of 14.3.1 shall apply to the distance between the rivets at their points and the maximum penetration requirement of 14.1.3.2 shall apply. The reference lateral design value of the connection shall be calculated in accordance with 14.2 considering the connection to be a one sided timber rivet joint, with: (a) the number of rivets associated with the one plate equalling the total number of rivets at the joint, and (b) s p and s q determined as the distances between the rivets at their points. 14.2 Reference Design Values 14.2.1 Parallel to Grain Loading For timber rivet connections (one plate and rivets associated with it) where: (a) the load acts perpendicular to the axis of the timber rivets (b) member thicknesses, edge distances, end distances, and spacing are sufficient to develop full adjusted design values (see 14.3) (c) timber rivets are installed in the side grain of wood members the reference design value per rivet joint parallel to grain, P, shall be calculated as the lesser of reference rivet capacity, P r, and reference wood capacity, P w : Pr = 188 p 0.32 nr nc (14.2-1) Pw = reference wood capacity design values parallel to grain (Tables 14.2.1A through 14.2.1F) using wood member thickness for the member dimension in Tables 14.2.1A through 14.2.1F for connections with steel plates on opposite sides; and twice the wood member thickness for the member dimension in Tables 14.2.1A through 14.2.1F for connections having only one plate, lbs.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 133 where: p = depth of penetration of rivet in wood member (see Appendix M), in. = rivet length plate thickness 1/8" nr = number of rows of rivets parallel to direction of load nc = number of rivets per row Reference design values, P, for timber rivet connections parallel to grain shall be multiplied by all applicable adjustment factors (see Table 11.3.1) to obtain adjusted design values, P'. 14.2.2 Perpendicular to Grain Loading For timber rivet connections (one plate and rivets associated with it) where: (a) the load acts perpendicular to the axis of the timber rivets (b) member thicknesses, edge distances, end distances, and spacing are sufficient to develop full adjusted design values (see 14.3) (c) timber rivets are installed in the side grain of wood members the reference design value per rivet joint perpendicular to grain, Q, shall be calculated as the lesser of reference rivet capacity, Q r, and reference wood capacity, Q w. Qr = 108 p 0.32 nr nc (14.2-2) Qw = qw p 0.8 C (14.2-3) Reference design values, Q, for timber rivet connections perpendicular to grain shall be multiplied by all applicable adjustment factors (see Table 11.3.1) to obtain adjusted design values, Q'. 14.2.3 Metal Side Plate Factor, Cst The reference design value parallel to grain, P, or perpendicular to grain, Q, for timber rivet connections, when reference rivet capacity (P r, Q r ) controls, shall be multiplied by the appropriate metal side plate factor, C st, specified in Table 14.2.3: Table 14.2.3 Metal Side Plate Factor, Cst, for Timber Rivet Connections Metal Side Plate Thickness, t s C st t s 1/4" 1.00 3/16" t s < 1/4" 0.90 1/8" t s < 3/16" 0.80 14.2.4 Load at Angle to Grain When a load acts in the plane of the wood surface at an angle,, to grain other than 0 or 90, the adjusted design value, N', for a timber rivet connection shall be determined as follows (see Appendix J): PQ N (14.2-4) Psin 2 Qcos 2 14.2.5 Timber Rivets in End Grain where: p = depth of penetration of rivet in wood member (see Appendix M), in. = rivet length plate thickness 1/8" nr = number of rows of rivets parallel to direction of load nc = number of rivets per row qw = value determined from Table 14.2.2A, lbs. C = geometry factor determined from Table 14.2.2B Where timber rivets are used in end grain, the factored lateral resistance of the joint shall be 50% of that for perpendicular to side grain applications where the slope of cut is 90 to the side grain. For sloping end cuts, these values can be increased linearly to 100% of the applicable parallel or perpendicular to side grain value. 14.2.6 Design of Metal Parts Metal parts shall be designed in accordance with applicable metal design procedures (see 11.2.3). TIMBER RIVETS 14

134 TIMBER RIVETS 14.3 Placement of Timber Rivets 14.3.1 Spacing Between Rivets Minimum spacing of rivets shall be 1/2" perpendicular to grain, s q, and 1" parallel to grain, sp. The maximum distance perpendicular to grain between outermost rows of rivets shall be 12". 14.3.2 End and Edge Distance Minimum values for end distance (a p, a q) and edge distance (e p, e q ) as shown and noted in Figure 14A, are listed in Table 14.3.2. Table 14.3.2 Minimum End and Edge Distances for Timber Rivet Joints Number of rivet rows, n R Load Parallel to grain, a P Minimum end distance, a, in. Load perpendicular to grain, a q Unloaded Edge e P Minimum edge distance, e, in. Loaded edge e q 1, 2 3 2 1 2 3 to 8 3 3 1 2 9, 10 4 3-1/8 1 2 11, 12 5 4 1 2 13, 14 6 4-3/4 1 2 15, 16 7 5-1/2 1 2 17 and greater 8 6-1/4 1 2 Note: End and edge distance requirements are shown in Figure 14A. Figure 14A End and Edge Distance Requirements for Timber Rivet Joints

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 135 Table 14.2.1A Member Thickness in. 3 5 6.75 8.5 and greater Reference Wood Capacity Design Values Parallel to Grain, P w, for Timber Rivets Rivet Length = 1-1/2" s p = 1" s q = 1" Rivets P w (lbs.) per row No. of rows per side 2 4 6 8 10 12 14 16 18 20 2 2050 4900 7650 10770 14100 17050 19760 22660 25690 28990 4 3010 6460 9700 13530 17450 20840 23870 27020 30530 34460 6 4040 8010 11770 16320 20870 24770 27950 31450 35710 40300 8 5110 9480 13970 18840 23910 28230 31990 35760 40130 45290 10 5900 10930 15880 21390 26940 32020 35660 40080 44830 50590 12 6670 12100 17760 23980 29980 35010 39780 44480 49570 55940 14 7310 13540 19400 26380 32740 38610 43090 48640 54720 61750 16 7670 14960 21380 28260 35470 41670 46310 52870 59350 66970 18 8520 16250 23290 30440 38010 44500 50050 56120 63840 70970 20 9030 17770 24950 32300 40160 46880 52590 59800 66880 74300 2 2680 5160 5980 7250 9280 10860 12470 15150 19410 24260 4 3930 6610 7610 9050 11460 13390 15110 17890 22090 26280 6 5280 8190 9290 10890 13770 15870 18080 21120 25640 29870 8 6690 9700 10940 12740 15950 18230 20580 23780 28450 32570 10 7720 11160 12550 14550 18120 20600 23140 26550 31500 36850 12 8730 12680 14170 16240 20100 23100 25410 29610 35000 40730 14 9560 14160 15720 17980 22210 25460 27940 32450 38220 44250 16 10030 15610 17330 19650 24200 27680 30320 35100 42230 48910 18 11150 17020 18770 21450 26110 29780 33140 38370 46160 51900 20 11800 18410 20310 23000 28270 32260 35900 41570 50030 56260 2 2930 4810 5550 6740 8630 10110 11610 14120 18080 22630 4 4300 6170 7080 8420 10680 12490 14100 16700 20630 24570 6 5780 7650 8640 10150 12840 14820 16890 19740 23980 27960 8 7320 9060 10190 11880 14890 17040 19250 22240 26630 30510 10 8440 10420 11690 13580 16920 19260 21640 24850 29500 34540 12 9540 11850 13210 15150 18780 21610 23780 27730 32800 38200 14 10450 13230 14650 16790 20760 23820 26170 30410 35830 41520 16 10970 14590 16160 18350 22630 25910 28410 32900 39610 45910 18 12190 15910 17510 20040 24420 27890 31050 35980 43310 48740 20 12910 17210 18950 21490 26450 30210 33650 38990 46950 52860 2 2930 4740 5460 6630 8500 9950 11440 13900 17810 22290 4 4300 6080 6970 8290 10520 12300 13890 16450 20330 24210 6 5780 7530 8510 10000 12650 14600 16640 19460 23630 27560 8 7320 8920 10030 11700 14670 16790 18970 21930 26250 30080 10 8440 10270 11520 13370 16680 18980 21330 24500 29090 34060 12 9540 11670 13010 14930 18510 21300 23450 27340 32340 37670 14 10450 13040 14430 16540 20460 23480 25800 29980 35340 40960 16 10970 14370 15920 18080 22310 25540 28010 32450 39060 45290 18 12190 15670 17250 19750 24070 27490 30620 35480 42720 48090 20 12910 16950 18670 21180 26070 29790 33190 38460 46310 52150 TIMBER RIVETS 14 Note: Member dimension is identified as b in Figure 14A for connections with steel side plates on opposite sides. For connections having only one plate, member dimension is twice the thickness of the wood member. Linear interpolation for intermediate values shall be permitted.

136 TIMBER RIVETS Table 14.2.1B Member Thickness in. 3 5 6.75 8.5 and greater Reference Wood Capacity Design Values Parallel to Grain, P w, for Timber Rivets Rivet Length = 1-1/2" s p = 1-1/2" s q = 1" Rivets P w (lbs.) per row No. of rows per side 2 4 6 8 10 12 14 16 18 20 2 2320 5650 8790 12270 16000 19800 23200 26100 29360 33180 4 3420 7450 11150 15420 19810 24200 28020 31130 34900 39430 6 4580 9230 13530 18600 23690 28760 32810 36230 40810 46120 8 5810 10920 16060 21480 27150 32780 37550 41200 45860 51830 10 6700 12600 18250 24380 30590 37180 41870 46180 51230 57890 12 7570 13940 20420 27340 34040 40650 46700 51250 56650 64020 14 8290 15600 22310 30070 37180 44840 50590 56040 62540 70670 16 8710 17250 24580 32220 40280 48400 54360 60910 67820 76650 18 9680 18720 26770 34700 43150 51680 58750 64660 72960 81220 20 10250 20480 28680 36820 45600 54450 61740 68900 76440 85030 2 3040 5360 6740 8600 11930 14870 18310 23450 32100 42850 4 4470 7660 9560 11970 16430 20450 24740 30870 40740 51580 6 5990 9910 12180 15050 20610 25320 30910 38070 49400 60320 8 7590 12000 14680 18020 24440 29760 36020 43870 56110 67790 10 8760 14010 17090 20880 28170 34120 41080 49700 63030 75720 12 9900 16080 19480 23530 31570 38650 45570 55990 70740 83740 14 10850 18080 21770 26240 35120 42890 50480 61810 77820 92440 16 11390 20040 24140 28830 38490 46900 55080 67230 86450 100250 18 12660 21950 26250 31620 41690 50680 60450 73800 94910 106230 20 13400 23810 28500 34010 45310 55090 65720 80250 99970 111210 2 3320 5000 6260 8000 11110 13850 17060 21870 29940 39990 4 4890 7150 8900 11150 15330 19090 23110 28850 38090 48440 6 6560 9250 11340 14040 19240 23660 28900 35620 46240 57570 8 8310 11210 13680 16810 22840 27840 33710 41080 52570 64320 10 9580 13090 15930 19500 26330 31930 38470 46570 59100 73900 12 10830 15020 18170 21980 29520 36180 42700 52490 66360 82550 14 11860 16900 20310 24520 32860 40180 47320 57980 73030 90400 16 12460 18730 22520 26950 36030 43940 51650 63090 81170 100510 18 13840 20520 24500 29560 39040 47500 56710 69290 89150 107180 20 14660 22270 26610 31810 42440 51650 61680 75360 96980 116640 2 3320 4930 6160 7880 10930 13640 16810 21540 29490 39400 4 4890 7050 8760 10990 15100 18800 22770 28430 37540 47750 6 6560 9110 11170 13830 18960 23310 28490 35110 45590 56770 8 8310 11040 13480 16560 22510 27440 33230 40510 51840 63430 10 9580 12890 15690 19210 25960 31480 37930 45920 58280 72900 12 10830 14800 17900 21660 29100 35670 42110 51770 65450 81440 14 11860 16650 20000 24170 32390 39610 46670 57190 72040 89190 16 12460 18450 22190 26560 35520 43330 50940 62240 80080 99190 18 13840 20220 24140 29140 38490 46850 55940 68350 87960 105780 20 14660 21940 26220 31360 41840 50940 60840 74350 95690 115120 Note: Member dimension is identified as b in Figure 14A for connections with steel side plates on opposite sides. For connections having only one plate, member dimension is twice the thickness of the wood member. Linear interpolation for intermediate values shall be permitted.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 137 Table 14.2.1C Member Thickness in. 5 6.75 8.5 10.5 12.5 and greater Reference Wood Capacity Design Values Parallel to Grain, P w, for Timber Rivets Rivet Length = 2-1/2" s p = 1" s q = 1" Rivets per P w (lbs.) row No. of rows per side 2 4 6 8 10 12 14 16 18 20 2 2340 5610 8750 12310 16120 19500 22600 25910 29380 33160 4 3440 7390 11100 15470 19950 23830 27290 30900 34920 39400 6 4620 9160 13460 18660 23860 28320 31970 35960 40830 46080 8 5850 10840 15980 21550 27350 32280 36580 40900 45890 51790 10 6750 12500 18160 24460 30810 36610 40780 45840 51260 57850 12 7630 13830 20310 27420 34280 40030 45490 50870 56690 63970 14 8360 15480 22190 30170 37450 44150 49280 55620 62580 70620 16 8770 17110 24450 32320 40570 47660 52960 60450 67870 76590 18 9750 18580 26630 34810 43460 50890 57230 64170 73010 81160 20 10320 20320 28530 36940 45920 53610 60140 68380 76480 84960 2 2710 6490 10130 14260 18660 22570 26170 30000 34020 38390 4 3980 8550 12850 17910 22580 26120 29190 34220 40420 45620 6 5350 10600 15590 20390 25510 29030 32670 37760 45400 52330 8 6770 12550 18500 22880 28260 31840 35470 40500 47980 54310 10 7810 14480 21020 25280 30980 34680 38400 43540 51130 59140 12 8830 16020 23510 27430 33360 37720 40900 47070 55050 63330 14 9670 17920 25690 29640 35930 40500 43810 50240 58540 67000 16 10160 19810 28310 31700 38300 43040 46460 53110 63200 72360 18 11290 21510 30160 33950 40490 45390 49750 56870 67670 75240 20 11950 23530 32140 35770 43070 48280 52920 60500 72000 80080 2 3070 7350 10580 13060 16620 19300 21990 26530 33760 41900 4 4510 9690 12400 14710 18410 21240 23720 27810 34060 40180 6 6060 12000 14390 16700 20790 23640 26610 30780 37040 42750 8 7670 13920 16320 18720 23050 25970 28960 33100 39250 44510 10 8850 15730 18150 20680 25290 28330 31420 35660 41930 48600 12 10010 17590 19970 22430 27270 30870 33520 38630 45240 52180 14 10960 19360 21660 24250 29400 33190 35960 41310 48200 55320 16 11510 21050 23410 25950 31370 35320 38200 43740 52130 59860 18 12790 22670 24900 27810 33200 37290 40960 46920 55920 62350 20 13540 24220 26510 29310 35350 39720 43640 49990 59580 66480 2 3400 7730 9830 11980 15210 17650 20110 24260 30870 38340 4 5000 9490 11460 13490 16860 19460 21740 25500 31230 36880 6 6710 11400 13250 15310 19060 21690 24430 28270 34030 39320 8 8490 13150 15020 17170 21150 23850 26610 30440 36110 41000 10 9800 14810 16700 18980 23230 26040 28900 32840 38630 44830 12 11080 16520 18360 20600 25060 28400 30870 35610 41730 48190 14 12130 18140 19910 22280 27040 30560 33150 38110 44500 51140 16 12740 19680 21520 23850 28870 32550 35240 40390 48170 55390 18 14160 21160 22900 25570 30570 34390 37820 43350 51710 57750 20 14990 22580 24380 26970 32570 36640 40310 46220 55140 61620 2 3540 7610 9540 11590 14710 17060 19440 23450 29840 37060 4 5210 9300 11100 13040 16300 18820 21030 24670 30230 35700 6 6990 11140 12840 14810 18440 20990 23650 27370 32960 38100 8 8860 12840 14540 16620 20470 23090 25780 29490 35000 39750 10 10220 14440 16160 18370 22490 25230 28010 31830 37450 43490 12 11550 16090 17770 19940 24270 27520 29920 34530 40470 46760 14 12650 17650 19270 21580 26190 29620 32150 36970 43180 49650 16 13290 19140 20840 23100 27970 31560 34180 39190 46760 53800 18 14760 20570 22170 24770 29630 33350 36690 42080 50210 56110 20 15630 21940 23600 26130 31570 35550 39120 44880 53560 59880 TIMBER RIVETS 14 Note: Member dimension is identified as b in Figure 14A for connections with steel side plates on opposite sides. For connections having only one plate, member dimension is twice the thickness of the wood member. Linear interpolation for intermediate values shall be permitted.

138 TIMBER RIVETS Table 14.2.1D Member Thickness in. Note: 5 6.75 8.5 10.5 12.5 and greater Reference Wood Capacity Design Values Parallel to Grain, P w, for Timber Rivets Rivet Length = 2-1/2" s p = 1-1/2" s q = 1" Rivets per P w (lbs.) row No. of rows per side 2 4 6 8 10 12 14 16 18 20 2 2660 6460 10050 14040 18300 22640 26530 29850 33580 37950 4 3910 8520 12750 17640 22650 27670 32040 35600 39900 45090 6 5240 10560 15480 21270 27090 32890 37530 41430 46670 52740 8 6640 12490 18370 24560 31050 37490 42940 47120 52450 59270 10 7660 14410 20870 27880 34980 42520 47880 52810 58580 66200 12 8660 15950 23350 31260 38920 46490 53400 58610 64790 73210 14 9480 17840 25510 34390 42520 51270 57850 64080 71520 80820 16 9960 19720 28110 36850 46060 55340 62170 69650 77560 87650 18 11070 21410 30610 39680 49350 59090 67180 73940 83440 92880 20 11720 23420 32800 42110 52140 62260 70600 78790 87410 97230 2 3070 7480 11640 16250 21190 26210 30720 34560 38880 43930 4 4520 9860 14770 20420 26230 32040 37100 41220 46200 52210 6 6070 12220 17920 24630 31370 38080 43450 47970 54030 61060 8 7690 14460 21260 28440 35950 43400 49720 54550 60720 68620 10 8870 16690 24160 32280 40500 49230 55430 61150 67820 76650 12 10030 18460 27030 36200 45060 53820 61830 67860 75010 84760 14 10980 20660 29530 39820 49220 59360 66980 74190 82800 93570 16 11530 22830 32550 42660 53320 64070 71980 80640 89800 101480 18 12810 24790 35440 45940 57130 68420 77780 85600 96600 107530 20 13560 27110 37970 48750 60370 72080 81740 91220 101200 112570 2 3480 8230 11610 14990 20600 25440 31030 39170 44060 49790 4 5120 11170 14980 18590 25140 30870 36920 45610 52360 59170 6 6880 13850 18020 21920 29500 35710 43060 52490 61230 69190 8 8710 16390 20820 25060 33380 40030 47840 57640 68810 77760 10 10050 18910 23430 28020 37080 44230 52570 62910 76860 86860 12 11360 20920 25960 30640 40320 48610 56590 68770 85000 96060 14 12440 23410 28300 33320 43740 52600 61110 74030 92320 106040 16 13070 25860 30710 35810 46880 56250 65240 78780 100360 115000 18 14520 27900 32770 38510 49810 59620 70230 84840 108100 121860 20 15370 29860 34970 40700 53190 63690 75060 90690 114690 127580 2 3860 7930 10760 13740 18860 23280 28400 36090 48770 55110 4 5670 10740 13810 17050 23050 28310 33880 41870 54800 65490 6 7610 13360 16580 20110 27080 32800 39590 48290 62110 76590 8 9640 15700 19140 23010 30670 36830 44050 53110 67340 81680 10 11130 17870 21540 25740 34110 40740 48470 58060 72990 90530 12 12580 20050 23860 28170 37130 44820 52230 63540 79580 98220 14 13770 22110 26020 30660 40300 48540 56460 68470 85450 104980 16 14460 24060 28240 32970 43240 51950 60330 72930 92990 114320 18 16070 25920 30140 35470 45960 55110 65010 78610 100260 119710 20 17020 27710 32170 37520 49120 58920 69530 84110 107290 128200 2 4020 7800 10440 13290 18230 22500 27450 34890 47430 57470 4 5920 10500 13370 16490 22300 27390 32790 40540 53060 66920 6 7940 13040 16050 19460 26210 31770 38350 46780 60200 74320 8 10060 15300 18530 22270 29710 35680 42690 51500 65300 79260 10 11600 17390 20850 24930 33050 39490 47000 56320 70830 87900 12 13120 19490 23110 27290 35980 43460 50680 61670 77270 95420 14 14370 21480 25200 29700 39080 47090 54800 66480 83000 102030 16 15080 23370 27350 31950 41930 50420 58580 70850 90360 111160 18 16760 25170 29200 34380 44590 53500 63140 76390 97460 116450 20 17750 26900 31170 36380 47660 57220 67550 81760 104330 124740 Member dimension is identified as b in Figure 14A for connections with steel side plates on opposite sides. For connections having only one plate, member dimension is twice the thickness of the wood member. Linear interpolation for intermediate values shall be permitted.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 139 Table 14.2.1E Member Thickness in. 6.75 8.5 10.5 12.5 14.5 and greater Reference Wood Capacity Design Values Parallel to Grain, P w, for Timber Rivets Rivet Length = 3-1/2" s p = 1" s q = 1" Rivets per P w (lbs.) row No. of rows per side 2 4 6 8 10 12 14 16 18 20 2 2440 5850 9130 12850 16820 20350 23590 27040 30670 34610 4 3590 7710 11580 16150 20820 24870 28490 32250 36450 41130 6 4820 9560 14050 19480 24910 29560 33370 37540 42620 48100 8 6100 11310 16680 22490 28550 33700 38180 42690 47900 54060 10 7040 13050 18950 25530 32160 38220 42570 47850 53510 60380 12 7960 14440 21200 28630 35780 41780 47480 53100 59170 66770 14 8720 16160 23160 31490 39090 46090 51440 58050 65320 73710 16 9160 17860 25530 33740 42340 49740 55280 63100 70840 79940 18 10170 19390 27790 36330 45370 53120 59740 66990 76210 84710 20 10770 21210 29780 38560 47930 55960 62770 71380 79830 88680 2 2710 6490 10130 14250 18660 22570 26160 29990 34010 38380 4 3980 8550 12840 17910 23090 27580 31600 35770 40420 45610 6 5350 10600 15590 21600 27620 32790 37000 41630 47270 53350 8 6770 12550 18500 24940 31660 37370 42350 47340 53120 59950 10 7810 14480 21020 28320 35670 42390 47210 53060 59340 66970 12 8830 16020 23510 31750 39680 46340 52660 58890 65620 74060 14 9670 17920 25690 34920 43350 51110 57050 64390 72440 81750 16 10160 19810 28310 37420 46960 55170 61310 69980 78560 88660 18 11280 21510 30830 40300 50310 58910 66250 74290 84510 93950 20 11950 23520 33030 42760 53160 62060 69620 79160 88540 98360 2 3020 7240 11300 15900 20820 25180 29190 33460 37940 42820 4 4440 9540 14330 19980 25760 30770 35250 39900 45090 50890 6 5960 11830 17390 24100 30820 36580 41280 46440 52740 59510 8 7550 14000 20630 27830 35320 40570 44460 49980 58370 65230 10 8720 16150 23450 31420 38000 41760 45450 50740 58770 67160 12 9850 17870 26230 32850 39220 43470 46330 52530 60650 68990 14 10790 19990 28660 34370 40770 45050 47920 54190 62370 70660 16 11330 22100 31580 35730 42190 46510 49400 55710 65540 74330 18 12590 23990 33750 37340 43510 47850 51650 58300 68630 75640 20 13330 26240 35340 38490 45290 49850 53850 60830 71650 79050 2 3320 7960 12420 17490 22890 27690 32090 36790 41720 47090 4 4890 10490 15760 21970 28330 33840 38760 43880 49590 55960 6 6560 13010 19120 25230 31370 35100 38780 44070 52180 59340 8 8310 15390 22350 26580 32170 35480 38780 43560 50870 56880 10 9580 17760 24250 27850 33280 36450 39640 44260 51300 58690 12 10830 19650 25950 28920 34280 37940 40440 45890 53030 60430 14 11870 21990 27400 30150 35610 39340 41890 47420 54640 62020 16 12460 24300 28890 31290 36860 40660 43240 48840 57520 65380 18 13840 26360 30040 32670 38030 41880 45280 51190 60340 66660 20 14660 28020 31320 33670 39620 43680 47270 53490 63100 69790 2 3580 8580 13390 18850 24670 29840 34590 39650 44970 50750 4 5270 11020 16940 22830 29290 33640 37040 42730 51500 59860 6 7070 13590 19540 23990 29520 32900 36290 41210 48800 55490 8 8950 15930 21540 25060 30160 33200 36280 40760 47610 53260 10 10330 18090 23150 26150 31160 34110 37110 41450 48060 55040 12 11680 20230 24620 27120 32090 35530 37890 43020 49740 56740 14 12790 22170 25890 28250 33350 36870 39280 44500 51310 58300 16 13430 23950 27220 29310 34540 38120 40580 45870 54070 61530 18 14920 25580 28250 30610 35650 39300 42530 48120 56770 62800 20 15800 27070 29430 31550 37160 41020 44440 50330 59420 65810 TIMBER RIVETS 14 Note: Member dimension is identified as b in Figure 14A for connections with steel side plates on opposite sides. For connections having only one plate, member dimension is twice the thickness of the wood member. Linear interpolation for intermediate values shall be permitted.

140 TIMBER RIVETS Table 14.2.1F Member Thickness in. 14.5 and greater Note: 6.75 8.5 10.5 12.5 Reference Wood Capacity Design Values Parallel to Grain, P w, for Timber Rivets Rivet Length = 3-1/2" s p = 1-1/2" s q = 1" Rivets per P w (lbs.) row No. of rows per side 2 4 6 8 10 12 14 16 18 20 2 2770 6740 10490 14650 19100 23630 27690 31160 35050 39610 4 4080 8890 13310 18410 23640 28880 33440 37160 41650 47070 6 5470 11020 16160 22200 28280 34330 39170 43250 48710 55050 8 6930 13040 19170 25640 32410 39130 44820 49180 54740 61860 10 8000 15040 21780 29110 36510 44380 49970 55130 61150 69100 12 9040 16640 24370 32630 40630 48520 55740 61180 67620 76420 14 9900 18630 26630 35900 44380 53520 60390 66890 74650 84360 16 10390 20590 29340 38460 48080 57770 64890 72710 80960 91490 18 11550 22350 31950 41420 51510 61680 70130 77180 87090 96950 20 12230 24450 34230 43960 54430 64990 73690 82240 91240 101490 2 3070 7480 11640 16250 21190 26210 30710 34560 38870 43930 4 4520 9860 14760 20420 26220 32030 37090 41210 46190 52200 6 6070 12220 17920 24630 31360 38080 43440 47960 54020 61050 8 7690 14460 21260 28440 35950 43400 49710 54550 60710 68610 10 8870 16680 24160 32280 40500 49220 55420 61140 67820 76640 12 10020 18460 27030 36190 45060 53820 61820 67850 75000 84750 14 10980 20660 29530 39810 49220 59360 66970 74180 82790 93560 16 11530 22830 32540 42660 53320 64070 71970 80630 89790 101460 18 12810 24790 35440 45940 57130 68410 77770 85600 96590 107520 20 13560 27110 37970 48750 60360 72070 81730 91210 101190 112560 2 3430 8340 12980 18130 23640 29240 34260 38550 43360 49000 4 5040 11000 16470 22780 29250 35740 41380 45980 51530 58240 6 6770 13630 19990 27470 34990 42480 48460 53510 60270 68110 8 8570 16130 23720 31720 40100 48420 55460 60850 67730 76540 10 9890 18610 26950 36010 45180 54910 61830 68210 75660 85500 12 11180 20590 30150 40380 50270 60040 68970 75690 83670 94550 14 12250 23040 32940 43530 54910 65690 74710 82760 92360 104370 16 12860 25470 36300 45490 58120 68370 78030 89950 100170 113190 18 14290 27650 39530 47750 60310 70840 82200 95490 107750 119950 20 15130 30250 42360 49450 63130 74240 86230 101750 112880 125570 2 3770 8940 14280 19930 25990 32150 37680 42390 47680 53890 4 5550 12090 18110 25050 32170 39300 45500 50560 56670 64040 6 7440 14990 21980 30210 38480 46710 53290 58840 66270 74890 8 9430 17740 26080 32640 42400 49720 58300 66910 74480 84170 10 10880 20470 29450 34550 44560 52030 60770 71680 83190 94020 12 12300 22640 31480 36220 46470 54910 62900 75440 92000 103970 14 13470 25340 33270 38080 48780 57570 65900 78860 97350 114770 16 14140 28010 35150 39800 50920 60030 68660 81990 103470 124470 18 15710 30410 36640 41810 52910 62310 72460 86620 109420 129590 20 16640 33260 38300 43320 55450 65400 76150 91130 115220 136640 2 4060 8940 15370 21480 28010 34650 40610 45690 51390 58080 4 5980 12730 19520 26990 34670 42350 49040 54490 61080 69020 6 8020 16160 23590 28890 37960 44900 53060 63410 71430 80720 8 10160 19120 25880 30610 39690 46550 54610 64800 80270 90710 10 11720 21820 27800 32370 41740 48760 56990 67280 83550 101330 12 13250 24280 29620 33930 43560 51520 59070 70900 87820 107340 14 14520 26450 31250 35680 45760 54070 61960 74220 91690 111670 16 15240 28390 32980 37310 47800 56430 64630 77250 97570 119050 18 16940 30160 34370 39220 49710 58630 68270 81700 103290 122520 20 17930 31770 35920 40670 52140 61590 71820 86040 108880 129320 Member dimension is identified as b in Figure 14A for connections with steel side plates on opposite sides. For connections having only one plate, member dimension is twice the thickness of the wood member. Linear interpolation for intermediate values shall be permitted.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 141 Table 14.2.2A Values of q w (lbs) Perpendicular to Grain for Timber Rivets sp = 1" s q in. 1 1-1/2 Rivets per Number of rows 2 4 6 8 10 row 2 776 809 927 1089 1255 3 768 806 910 1056 1202 4 821 870 963 1098 1232 5 874 923 1013 1147 1284 6 959 1007 1094 1228 1371 7 1048 1082 1163 1297 1436 8 1173 1184 1256 1391 1525 9 1237 1277 1345 1467 1624 10 1318 1397 1460 1563 1752 11 1420 1486 1536 1663 1850 12 1548 1597 1628 1786 1970 13 1711 1690 1741 1882 2062 14 1924 1802 1878 1997 2170 15 2042 1937 1963 2099 2298 16 2182 2102 2063 2218 2449 17 2350 2223 2178 2313 2541 18 2553 2365 2313 2422 2644 19 2524 2432 2407 2548 2762 20 2497 2506 2514 2692 2897 2 1136 1097 1221 1414 1630 3 1124 1093 1199 1371 1561 4 1202 1180 1268 1426 1601 5 1280 1251 1334 1490 1668 6 1404 1366 1442 1595 1780 7 1534 1467 1532 1685 1865 8 1717 1606 1654 1806 1980 9 1811 1731 1772 1905 2110 10 1929 1894 1923 2030 2275 11 2078 2016 2023 2159 2403 12 2265 2166 2145 2319 2559 13 2504 2292 2293 2444 2678 14 2817 2444 2473 2593 2818 15 2989 2627 2586 2725 2984 16 3193 2850 2717 2880 3181 17 3439 3014 2869 3004 3300 18 3737 3207 3047 3146 3434 19 3695 3298 3171 3309 3588 20 3655 3398 3311 3496 3762 Table 14.2.2B Geometry Factor, C D, for Timber Rivet Connections Loaded Perpendicular to Grain ep ( nc -1) S 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.2 1.4 1.6 1.8 2.0 2.4 2.8 q C ep ( nc -1) Sq C 5.76 3.2 0.79 3.19 3.6 0.77 2.36 4.0 0.76 2.00 5.0 0.72 1.77 6.0 0.70 1.61 7.0 0.68 1.47 8.0 0.66 1.36 9.0 0.64 1.28 10.0 0.63 1.20 12.0 0.61 1.10 14.0 0.59 1.02 16.0 0.57 0.96 18.0 0.56 0.92 20.0 0.55 0.89 25.0 0.53 0.85 30.0 0.51 0.81 TIMBER RIVETS 14

142 TIMBER RIVETS

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 143 SPECIAL LOADING CONDITIONS 15.1 Lateral Distribution of a Concentrated Load 144 15.2 Spaced Columns 144 15.3 Built-Up Columns 146 15.4 Wood Columns with Side Loads and Eccentricity 149 Table 15.1.1 Lateral Distribution Factors for Moment... 144 Table 15.1.2 Lateral Distribution in Terms of Proportion of Total Load... 144 15

144 SPECIAL LOADING CONDITIONS 15.1 Lateral Distribution of a Concentrated Load 15.1.1 Lateral Distribution of a Concentrated Load for Moment When a concentrated load at the center of the beam span is distributed to adjacent parallel beams by a wood or concrete-slab floor, the load on the beam nearest the point of application shall be determined by multiplying the load by the following factors: Table 15.1.1 Lateral Distribution Factors for Moment 15.1.2 Lateral Distribution of a Concentrated Load for Shear When the load distribution for moment at the center of a beam is known or assumed to correspond to specific values in the first two columns of Table 15.1.2, the distribution to adjacent parallel beams when loaded at or near the quarter point (the approximate point of maximum shear) shall be assumed to be the corresponding values in the last two columns of Table 15.1.2. Load on Critical Beam Kind of Floor (for one traffic lane 2 ) 2" plank S/4.0 1 4" nail laminated S/4.5 1 6" nail laminated S/5.0 1 Concrete, structurally designed S/6.0 1 1. S = average spacing of beams, ft. If S exceeds the denominator of the factor, the load on the two adjacent beams shall be the reactions of the load, with the assumption that the floor slab between the beams acts as a simple beam. 2. See Reference 48 for additional information concerning two or more traffic lanes. Table 15.1.2 Lateral Distribution in Terms of Proportion of Total Load Load Applied at Center of Span Center Beam Distribution to Side Beams Load Applied at 1/4 Point of Span Center Beam Distribution to Side Beams 1.00 0 1.00 0 0.90 0.10 0.94 0.06 0.80 0.20 0.87 0.13 0.70 0.30 0.79 0.21 0.60 0.40 0.69 0.31 0.50 0.50 0.58 0.42 0.40 0.60 0.44 0.56 0.33 0.67 0.33 0.67 15.2 Spaced Columns 15.2.1 General 15.2.1.1 The design load for a spaced column shall be the sum of the design loads for each of its individual members. 15.2.1.2 The increased load capacity of a spaced column due to the end-fixity developed by the split ring or shear plate connectors and end blocks is effective only in the direction perpendicular to the wide faces of the individual members (direction parallel to dimension d 1, in Figure 15A). The capacity of a spaced column in the direction parallel to the wide faces of the individual members (direction parallel to dimension d 2 in Figure 15A) shall be subject to the provisions for simple solid columns, as set forth in 15.2.3.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 145 Figure 15A Spaced Column Joined by Split Ring or Shear Plate Connectors ½ the distance between centers of split ring or shear plate connectors in the end blocks. 15.2.2.3 For spaced columns used as compression members of a truss, a panel point which is stayed laterally shall be considered as the end of the spaced column, and the portion of the web members, between the individual pieces making up a spaced column, shall be permitted to be considered as the end blocks. 15.2.2.4 Thickness of spacer and end blocks shall not be less than that of individual members of the spaced column nor shall thickness, width, and length of spacer and end blocks be less than required for split ring or shear plate connectors of a size and number capable of carrying the load computed in 15.2.2.5. 15.2.2.5 To obtain spaced column action the split ring or shear plate connectors in each mutually contacting surface of end block and individual member at each end of a spaced column shall be of a size and number to provide a load capacity in pounds equal to the required cross-sectional area in square inches of one of the individual members times the appropriate end spacer block constant, K S, determined from the following equations: Condition "a": end distance 1 /20 1 and 2 = distances between points of lateral support in planes 1 and 2, measured from center to center of lateral supports for continuous spaced columns, and measured from end to end for simple spaced columns, inches. 3 = Distance from center of spacer block to centroid of the group of split ring or shear plate connectors in end blocks, inches. d 1 and d 2 = cross-sectional dimensions of individual rectangular compression members in planes of lateral support, inches. Condition "b": 1 /20 < end distance 1 /10 15.2.2 Spacer and End Block Provisions 15.2.2.1 Spaced columns shall be classified as to end fixity either as condition a or condition b (see Figure 15A), as follows: (a) For condition a, the centroid of the split ring or shear plate connector, or the group of connectors, in the end block shall be within 1 /20 from the column end. (b) For condition b, the centroid of the split ring or shear plate connector, or the group of connectors, in the end block shall be between 1 /20 and 1/10 from the column end. 15.2.2.2 Where a single spacer block is located within the middle 1/10 of the column length, 1, split ring or shear plate connectors shall not be required for this block. If there are two or more spacer blocks, split ring or shear plate connectors shall be required and the distance between two adjacent blocks shall not exceed Species Group End Spacer Block Constant, K S A K S = 9.55 ( 1 /d 1 11) 468 B K S = 8.14 ( 1 /d 1 11) 399 C K S = 6.73 ( 1 /d 1 11) 330 D K S = 5.32 ( 1 /d 1 11) 261 If spaced columns are a part of a truss system or other similar framing, the split ring or shear plate connectors required by the connection provisions in Chapter 13 of this Specification shall be checked against the end spacer block constants, K S, specified above. 15.2.3 Column Stability Factor, CP 15.2.3.1 The effective column length, e, for a spaced column shall be determined in accordance with principles of engineering mechanics. One method for determining effective column length, when end-fixity conditions are known, is to multiply actual column length by the appropriate effective length factor specified in Appendix G, e = (K e)( ), except that the effective column length, e, shall not be less than the actual column length,. 15.2.3.2 For individual members of a spaced column (see Figure 15A): (a) 1/d 1 shall not exceed 80, where 1 is the dis- SPECIAL LOADING CONDITIONS 15

146 SPECIAL LOADING CONDITIONS tance between lateral supports that provide restraint perpendicular to the wide faces of the individual members. (b) 2/d 2 shall not exceed 50, where 2 is the distance between lateral supports that provide restraint in a direction parallel to the wide faces of the individual members. (c) 3/d 1 shall not exceed 40, where 3 is the distance between the center of the spacer block and the centroid of the group of split ring or shear plate connectors in an end block. 15.2.3.3 The column stability factor shall be calculated as follows: C P 2 * * * ce c ce c ce c 1 F F 1 F F F F 2c 2c c where: (15.2-1) Fc * = reference compression design value parallel to grain multiplied by all applicable adjustment factors except CP (see 2.3) FcE = 0.822 Kx E /d e min 2 Kx = 2.5 for fixity condition a = 3.0 for fixity condition b c = 0.8 for sawn lumber = 0.9 for structural glued laminated timber or structural composite lumber 15.2.3.4 Where individual members of a spaced column are of different species, grades, or thicknesses, the lesser adjusted compression parallel to grain design value, F c ', for the weaker member shall apply to both members. 15.2.3.5 The adjusted compression parallel to grain design value, F c ', for a spaced column shall not exceed the adjusted compression parallel to grain design value, F c ', for the individual members evaluated as solid columns without regard to fixity in accordance with 3.7 using the column slenderness ratio 2 /d 2 (see Figure 15A). 15.2.3.6 For especially severe service conditions and/or extraordinary hazard, use of lower adjusted design values may be necessary. See Appendix H for background information concerning column stability calculations and Appendix F for information concerning coefficient of variation in modulus of elasticity (COV E ). 15.2.3.7 The equations in 3.9 for combined flexure and axial loading apply to spaced columns only for uniaxial bending in a direction parallel to the wide face of the individual member (dimension d 2 in Figure 15A). 15.3 Built-Up Columns 15.3.1 General The following provisions apply to nailed or bolted built-up columns with 2 to 5 laminations in which: (a) each lamination has a rectangular cross section and is at least 1-1/2" thick, t 1-1/2". (b) all laminations have the same depth (face width), d. (c) faces of adjacent laminations are in contact. (d) all laminations are full column length. (e) the connection requirements in 15.3.3 or 15.3.4 are met. Nailed or bolted built-up columns not meeting the preceding limitations shall have individual laminations designed in accordance with 3.6.3 and 3.7. Where individual laminations are of different species, grades, or thicknesses, the lesser adjusted compression parallel to grain design value, F c ', and modulus of elasticity for beam and column stability, E min ', for the weakest lamination shall apply. 15.3.2 Column Stability Factor, CP 15.3.2.1 The effective column length, e, for a built-up column shall be determined in accordance with principles of engineering mechanics. One method for determining effective column length, when end-fixity conditions are known, is to multiply actual column length by the appropriate effective length factor specified in Appendix G, e = (K e )( ). 15.3.2.2 The slenderness ratios e1/d 1 and e2 /d 2 (see Figure 15B) where each ratio has been adjusted by the appropriate buckling length coefficient, K e, from Appendix G, shall be determined. Each ratio shall be used to calculate a column stability factor, C P, per section 15.3.2.4 and the smaller C P shall be used in determining

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 147 the adjusted compression design value parallel to grain, Fc', for the column. F c ' for built-up columns need not be less than F c ' for the individual laminations designed as individual solid columns per section 3.7. 15.3.2.3 The slenderness ratio, e /d, for built-up columns shall not exceed 50, except that during construction e/d shall not exceed 75. 15.3.2.4 The column stability factor shall be calculated as follows: Figure 15B Mechanically Laminated Built- Up Columns C P 2 * * * 1 FcE Fc 1 FcE Fc FcE Fc Kf 2c 2c c where: (15.3-1) Fc* = reference compression design value parallel to grain multiplied by all applicable modification factors except CP (see 2.3) 0.822 E min FcE = 2 e /d Kf = 0.6 for built-up columns where e2/d2 is used to calculate FcE and the built-up columns are nailed in accordance with 15.3.3 Kf = 0.75 for built-up columns where e2/d2 is used to calculate FcE and the built-up columns are bolted in accordance with 15.3.4 Kf = 1.0 for built-up columns where e1/d1 is used to calculate FcE and the built-up columns are either nailed or bolted in accordance with 15.3.3 or 15.3.4, respectively c = 0.8 for sawn lumber c = 0.9 for structural glued laminated timber or structural composite lumber 15.3.2.5 For especially severe service conditions and/or extraordinary hazard, use of lower adjusted design values may be necessary. See Appendix H for background information concerning column stability calculations and Appendix F for information concerning coefficient of variation in modulus of elasticity (COV E ). 15.3.3 Nailed Built-Up Columns 15.3.3.1 The provisions in 15.3.1 and 15.3.2 apply to nailed built-up columns (see Figure 15C) in which: (a) adjacent nails are driven from opposite sides of the column (b) all nails penetrate all laminations and at least 3/4 of the thickness of the outermost lamination (c) 15D end distance 18D (d) 20D spacing between adjacent nails in a row 6t min (e) 10D spacing between rows of nails 20D (f) 5D edge distance 20D (g) 2 or more longitudinal rows of nails are provided where d > 3t min where: D = nail diameter d = depth (face width) of individual lamination tmin = thickness of thinnest lamination Where only one longitudinal row of nails is required, adjacent nails shall be staggered (see Figure 15C). Where three or more longitudinal rows of nails are used, nails in adjacent rows shall be staggered. SPECIAL LOADING CONDITIONS 15

148 SPECIAL LOADING CONDITIONS Figure 15C Typical Nailing Schedules for Built-Up Columns 15.3.4 Bolted Built-Up Columns 15.3.4.1 The provisions in 15.3.1 and 15.3.2 apply to bolted built-up columns in which: (a) a metal plate or washer is provided between the wood and the bolt head, and between the wood and the nut (b) nuts are tightened to insure that faces of adjacent laminations are in contact (c) for softwoods: 7D end distance 8.4D for hardwoods: 5D end distance 6D (d) 4D spacing between adjacent bolts in a row 6t min (e) 1.5D spacing between rows of bolts 10D (f) 1.5D edge distance 10D (g) 2 or more longitudinal rows of bolts are provided where d > 3t min where: D = bolt diameter d = depth (face width) of individual lamination tmin = thickness of thinnest lamination 15.3.4.2 Figure 15D provides an example of a bolting schedule which meets the preceding connection requirements. Figure 15D Typical Bolting Schedules for Built-Up Columns Four 2" x 8" laminations (softwoods) with two rows of ½" diameter bolts.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 149 15.4 Wood Columns with Side Loads and Eccentricity 15.4.1 General Equations and One design method that allows calculation of the direct compression load that an eccentrically loaded column, or one with a side load, is capable of sustaining is as follows: (a) Members subjected to a combination of bending from eccentricity and/or side loads about one or both principal axes, and axial compression, shall be proportioned so that: 2 f c fb1 f c(6e 1 / d 1)[1 0.234(f c /F ce1)] Fc Fb1 1 (f c /F ce1) for either uniaxial edgewise bending or biaxial bending (15.4-1) 2 f b1 f c(6e 1 / d 1) fb2 f c(6e 2 / d 2) 1 0.234(f c /F ce2) 0.234 FbE 1.0 2 fb1 f c(6e 1 / d 1) Fb2 1 (f c /F ce2) FbE and f c fb1 f c(6e 1 / d 1) FcE2 FbE 2 1.0 (15.4-2) (b) Members subjected to a combination of bending and compression from an eccentric axial load about one or both principal axes, shall be proportioned so that: 2 f c f c(6e 1 / d 1)[1 0.234(f c /F ce1)] Fc Fb1 1 (f c /F ce1) (15.4-3) 2 f c(6e 1 / d 1) f c(6e 2 / d 2) 1 0.234(f c /F ce2) 0.234 FbE 1.0 2 f c(6e 1 / d 1) Fb2 1 (f c /F ce2) FbE and f f (6e 1 / d 1) c c F ce2 FbE where: 0.822 E min fc < FcE1 = 2 e1 /d1 and 0.822 E min fc < FcE2 = 2 /d 2 e2 2 1.0 (15.4-4) for uniaxial flatwise bending or biaxial bending fb1 < FbE = 1.20 E R min 2 B for biaxial bending fc = compression stress parallel to grain due to axial load fb1 = edgewise bending stress due to side loads on narrow face only fb2 = flatwise bending stress due to side loads on wide face only Fc' = adjusted compression design value parallel to grain that would be permitted if axial compressive stress only existed, determined in accordance with 2.3 and 3.7 Fb1' = adjusted edgewise bending design value that would be permitted if edgewise bending stress only existed, determined in accordance with 2.3 and 3.3.3 Fb2' = adjusted flatwise bending design value that would be permitted if flatwise bending stress only existed, determined in accordance with 2.3 and 3.3.3 RB = slenderness ratio of bending member (see 3.3.3) d1 = wide face dimension d2 = narrow face dimension e1 = eccentricity, measured parallel to wide face from centerline of column to centerline of axial load e2 = eccentricity, measured parallel to narrow face from centerline of column to centerline of axial load Effective column lengths, e1 and e2, shall be determined in accordance with 3.7.1.2. F ce1 and F ce2 shall be determined in accordance with 3.7. F be shall be determined in accordance with 3.3.3. SPECIAL LOADING CONDITIONS 15

150 SPECIAL LOADING CONDITIONS 15.4.2 Columns with Side Brackets 15.4.2.1 The formulas in 15.4.1 assume that the eccentric load is applied at the end of the column. One design method that allows calculation of the actual bending stress, f b, if the eccentric load is applied by a bracket within the upper quarter of the length of the column is as follows. 5.4.2.2 Assume that a bracket load, P, at a distance, a, from the center of the column (Figure 15E), is replaced by the same load, P, centrally applied at the top of the column, plus a side load, P s, applied at midheight. Calculate P s from the following formula: 3P a p Ps (15.4-5) 2 Figure 15E Eccentrically Loaded Column where: P = actual load on bracket, lbs. Ps = assumed horizontal side load placed at center of height of column, lbs. a = horizontal distance from load on bracket to center of column, in. = total length of column, in. P = distance measured vertically from point of application of load on bracket to farther end of column, in. The assumed centrally applied load, P, shall be added to other concentric column loads, and the calculated side load, P s, shall be used to determine the actual bending stress, f b, for use in the formula for concentric end and side loading.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 151 FIRE DESIGN OF WOOD MEMBERS 16.1 General 152 16.2 Design Procedures for Exposed Wood Members 152 16.3 Wood Connections 154 Table 16.2.1A Effective Char Rates and Char Depths (for β n = 1.5 in./hr.)... 152 Table 16.2.1B Effective Char Depths (for CLT with β n = 1.5 in./hr.)... 153 Table 16.2.2 Adjustment Factors for Fire Design... 154 16

152 FIRE DESIGN OF WOOD MEMBERS 16.1 General Chapter 16 establishes general fire design provisions that apply to all wood structural members and connections covered under this Specification, unless otherwise noted. Each wood member or connection shall be of sufficient size and capacity to carry the applied loads without exceeding the design provisions specified herein. Reference design values and specific design provisions applicable to particular wood products or connections to be used with the provisions of this Chapter are given in other Chapters of this Specification. 16.2 Design Procedures for Exposed Wood Members The induced stress shall not exceed the resisting strength which have been adjusted for fire exposure. Wood member design provisions herein are limited to fire resistance calculations not exceeding 2 hours. 16.2.1 Char Rate 16.2.1.1 The effective char rate to be used in this procedure can be estimated from published nominal 1- hour char rate data using the following equation: 1.2n eff (16.2-1) 0.187 t where: eff = effective char rate (in./hr.), adjusted for exposure time, t n = nominal char rate (in./hr.), linear char rate based on 1-hour exposure t = exposure time (hr.) A nominal char rate, n, of 1.5 in./hr. is commonly assumed for solid sawn, structural glued laminated softwood members, laminated veneer lumber, parallel strand lumber, laminated strand lumber, and crosslaminated timber. 16.2.1.2 For solid sawn, structural glued laminated softwood, laminated veneer lumber, parallel strand lumber, and laminated strand lumber members with a nominal char rate, n = 1.5 in./hr., the effective char rates, eff, and effective char depths, a char, for each exposed surface are shown in Table 16.2.1A. Section properties shall be calculated using standard equations for area, section modulus, and moment of inertia using the reduced cross-sectional dimensions. The dimensions are reduced by the effective char layer thickness, a char, for each surface exposed to fire. Table 16.2.1A Required Fire Endurance (hr.) Effective Char Rates and Char Depths (for n = 1.5 in./hr.) Effective Char Rate, eff (in./hr.) Effective Char Depth, a char (in.) 1-Hour 1.8 1.8 1½-Hour 1.67 2.5 2-Hour 1.58 3.2 16.2.1.3 For cross-laminated timber, the effective char depth, a char, shall be calculated as follows: 0.813 a 1.2 n h t n t char lam lam n lam gi t gi where: and n h lam n 1.23 (16.2-2) tgi = time for char front to reach glued interface (hr.) hlam = lamination thickness (in.) lam t t gi nlam = number of laminations charred (rounded to lowest integer) t = exposure time (hr.) For cross-laminated timber manufactured with laminations of equal thickness and assuming a nominal char rate, n, of 1.5 in./hr., the effective char depths for each exposed surface are shown in Table 16.2.1B.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 153 Table 16.2.1B Required Fire Endurance (hr.) Effective Char Depths (for CLT with βn=1.5in./hr.) Effective Char Depths, a char (in.) lamination thicknesses, h lam (in.) 5/8 3/4 7/8 1 1-1/4 1-3/8 1-1/2 1-3/4 2 1-Hour 2.2 2.2 2.1 2.0 2.0 1.9 1.8 1.8 1.8 1½-Hour 3.4 3.2 3.1 3.0 2.9 2.8 2.8 2.8 2.6 2-Hour 4.4 4.3 4.1 4.0 3.9 3.8 3.6 3.6 3.6 16.2.1.4 Section properties shall be calculated using standard equations for area, section modulus, and moment of inertia using the reduced cross-sectional dimensions. The dimensions are reduced by the effective char depth, a char, for each surface exposed to fire. 16.2.1.5 For cross-laminated timber, reduced section properties shall be calculated using equations provided by the cross-laminated timber manufacturer based on the actual layup used in the manufacturing process. 16.2.2 Member Strength For solid sawn wood, structural glued laminated timber, structural composite lumber, and crosslaminated timber members, the average member strength can be approximated by multiplying reference design values (F b, F t, F c, F be, F ce ) by the adjustment factors specified in Table 16.2.2. The F b, F c, F be, and F ce values and cross-sectional properties shall be adjusted prior to use of Equations 3.3-6, 3.7-1, 3.9-1, 3.9-2, 3.9-3, 3.9-4, 15.2-1, 15.3-1, 15.4-1, 15.4-2, 15.4-3, or 15.4-4. 16.2.3 Design of Members The induced stress calculated using reduced section properties determined in 16.2.1 shall not exceed the member strength determined in 16.2.2. 16.2.4 Special Provisions for Structural Glued Laminated Timber Beams For structural glued laminated timber bending members given in Table 5A and rated for 1-hour fire endurance, an outer tension lamination shall be substituted for a core lamination on the tension side for unbalanced beams and on both sides for balanced beams. For structural glued laminated timber bending members given in Table 5A and rated for 1½- or 2-hour fire endurance, 2 outer tension laminations shall be substituted for 2 core laminations on the tension side for unbalanced beams and on both sides for balanced beams. 16.2.5 Provisions for Timber Decks Timber decks consist of planks that are at least 2" (actual) thick. The planks shall span the distance between supporting beams. Single and double tongueand-groove (T&G) decking shall be designed as an assembly of wood beams fully exposed on one face. Buttjointed decking shall be designed as an assembly of wood beams partially exposed on the sides and fully exposed on one face. To compute the effects of partial exposure of the decking on its sides, the char rate for this limited exposure shall be reduced to 33% of the effective char rate. These calculation procedures do not address thermal separation. FIRE DESIGN OF WOOD MEMBERS 16

154 FIRE DESIGN OF WOOD MEMBERS Table 16.2.2 Adjustment Factors for Fire Design 1 ASD Design Stress to Member Strength Factor Size Factor 2 Volume Factor 2 Flat Use Factor 2 Beam Stability Factor 3 Column Stability Factor 3 Bending Strength F b x 2.85 C F C V C fu C L - Beam Buckling Strength F be x 2.03 - - - - - Tensile Strength F t x 2.85 C F - - - - Compressive Strength F c x 2.58 C F - - - C P Column Buckling Strength F ce x 2.03 - - - - - 1. See 4.3, 5.3, 8.3, and 10.3 for applicability of adjustment factors for specific products. 2. Factor shall be based on initial cross-section dimensions. 3. Factor shall be based on reduced cross-section dimensions. 16.3 Wood Connections Where fire endurance is required, connectors and fasteners shall be protected from fire exposure by wood, fire-rated gypsum board, or any coating approved for the required endurance time.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 155 A APPENDIX A Construction and Design Practices 156 B Load Duration (ASD Only) 158 C Temperature Effects 160 D Lateral Stability of Beams 161 E Local Stresses in Fastener Groups 162 F Design for Creep and Critical Deflection Applications 167 G Effective Column Length 169 H Lateral Stability of Columns 170 I Yield Limit Equations for Connections 171 J Solution of Hankinson Formula 174 K Typical Dimensions for Split Ring and Shear Plate Connectors 177 L Typical Dimensions for Dowel-Type Fasteners and Washers 178 M Manufacturing Tolerances for Rivets and Steel Side Plates for Timber Rivet Connections 182 N Load and Resistance Factor Design (LRFD) 183 Table F1 Coefficients of Variation in Modulus of Elasticity (COV E ) for Lumber and Structural Glued Laminated Timber... 167 Table G1 Buckling Length Coefficients, K e... 169 Table I1 Fastener Bending Yield Strengths, F yb... 173 Tables L1 to L6 Typical Dimensions for Dowel-Type Fasteners and Washers... 178 Table N1 Format Conversion Factor, K F (LRFD Only)... 184 Table N2 Resistance Factor, φ (LRFD Only)... 184 Table N3 Time Effect Factor, λ (LRFD Only)... 184

156 APPENDIX Appendix A A.1 Care of Material (Non-mandatory) Construction and Design Practices L = truss span, ft Lumber shall be so handled and covered as to prevent marring and moisture absorption from snow or rain. A.2 Foundations A.2.1 Foundations shall be adequate to support the building or structure and any required loads, without excessive or unequal settlement or uplift. A.2.2 Good construction practices generally eliminate decay or termite damage. Such practices are designed to prevent conditions which would be conducive to decay and insect attack. The building site shall be graded to provide drainage away from the structure. All roots and scraps of lumber shall be removed from the immediate vicinity of the building before backfilling. A.3 Structural Design Consideration shall be given in design to the possible effect of cross-grain dimensional changes which may occur in lumber fabricated or erected in a green condition (i.e., provisions shall be made in the design so that if dimensional changes caused by seasoning to moisture equilibrium occur, the structure will move as a whole, and the differential movement of similar parts and members meeting at connections will be a minimum). A.4 Drainage In exterior structures, the design shall be such as to minimize pockets in which moisture can accumulate, or adequate caps, drainage, and drips shall be provided. A.5 Camber Adequate camber in trusses to give proper appearance and to counteract any deflection from loading should be provided. For timber connector construction, such camber shall be permitted to be estimated from the formula: where: 3 2 KL 1 KL 2 (A-1) H = camber at center of truss, in. H = truss height at center, ft K1 = 0.000032 for any type of truss K2 = 0.0028 for flat and pitched trusses K2 = 0.00063 for bowstring trusses (i.e., trusses without splices in upper chord) A.6 Erection A.6.1 Provision shall be made to prevent the overstressing of members or connections during erection. A.6.2 Bolted connections shall be snugly tightened, but not to the extent of crushing wood under washers. A.6.3 Adequate bracing shall be provided until permanent bracing and/or diaphragms are installed. A.7 Inspection Provision should be made for competent inspection of materials and workmanship. A.8 Maintenance There shall be competent inspection and tightening of bolts in connections of trusses and structural frames. A.9 Wood Column Bracing In buildings, for forces acting in a direction parallel to the truss or beam, column bracing shall be permitted to be provided by knee braces or, in the case of trusses, by extending the column to the top chord of the truss where the bottom and top chords are separated sufficiently to provide adequate bracing action. In a direction perpendicular to the truss or beam, bracing shall be permitted to be provided by wall construction, knee braces, or bracing between columns. Such bracing between columns should be installed preferably in the same bays as the bracing between trusses. A.10 Truss Bracing In buildings, truss bracing to resist lateral forces shall be permitted as follows: (a) Diagonal lateral bracing between top chords of trusses shall be permitted to be omitted when

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 157 the provisions of Appendix A.11 are followed or when the roof joists rest on and are securely fastened to the top chords of the trusses and are covered with wood sheathing. Where sheathing other than wood is applied, top chord diagonal lateral bracing should be installed. (b) In all cases, vertical sway bracing should be installed in each third or fourth bay at intervals of approximately 35 feet measured parallel to trusses. Also, bottom chord lateral bracing should be installed in the same bays as the vertical sway bracing, where practical, and should extend from side wall to side wall. In addition, struts should be installed between bottom chords at the same truss panels as vertical sway bracing and should extend continuously from end wall to end wall. If the roof construction does not provide proper top chord strut action, separate additional members should be provided. A.11.2 When planks are placed on top of an arch or compression chord, and securely fastened to the arch or compression chord, or when sheathing is nailed properly to the top chord of trussed rafters, the depth rather than the breadth of the arch, compression chord, or trussed rafter shall be permitted to be used as the least dimension in determining e/d. A.11.3 When stud walls in light frame construction are adequately sheathed on at least one side, the depth, rather than breadth of the stud, shall be permitted to be taken as the least dimension in calculating the e /d ratio. The sheathing shall be shown by experience to provide lateral support and shall be adequately fastened. A APPENDIX A.11 Lateral Support of Arches, Compression Chords of Trusses and Studs A.11.1 When roof joists or purlins are used between arches or compression chords, or when roof joists or purlins are placed on top of an arch or compression chord, and are securely fastened to the arch or compression chord, the largest value of e /d, calculated using the depth of the arch or compression chord or calculated using the breadth (least dimension) of the arch or compression chord between points of intermittent lateral support, shall be used. The roof joists or purlins should be placed to account for shrinkage (for example by placing the upper edges of unseasoned joists approximately 5% of the joist depth above the tops of the arch or chord), but also placed low enough to provide adequate lateral support.

158 APPENDIX Appendix B (Non-mandatory) Load Duration (ASD Only) B.1 Adjustment of Reference Design Values for Load Duration B.1.1 Normal Load Duration. The reference design values in this Specification are for normal load duration. Normal load duration contemplates fully stressing a member to its allowable design value by the application of the full design load for a cumulative duration of approximately 10 years and/or the application of 90% of the full design load continuously throughout the remainder of the life of the structure, without encroaching on the factor of safety. B.1.2 Other Load Durations. Since tests have shown that wood has the property of carrying substantially greater maximum loads for short durations than for long durations of loading, reference design values for normal load duration shall be multiplied by load duration factors, C D, for other durations of load (see Figure B1). Load duration factors do not apply to reference modulus of elasticity design values, E, nor to reference compression design values perpendicular to grain, F c, based on a deformation limit. (a) When the member is fully stressed to the adjusted design value by application of the full design load permanently, or for a cumulative total of more than 10 years, reference design values for normal load duration (except E and F c based on a deformation limit) shall be multiplied by the load duration factor, C D = 0.90. (b) Likewise, when the duration of the full design load does not exceed the following durations, reference design values for normal load duration (except E and F c based on a deformation limit) shall be multiplied by the following load duration factors: C D Load Duration 1.15 two months duration 1.25 seven days duration 1.6 ten minutes duration 2.0 impact (c) The 2 month load duration factor, C D = 1.15, is applicable to design snow loads based on ASCE 7. Other load duration factors shall be permitted to be used where such adjustments are referenced to the duration of the design snow load in the specific location being considered. (d) The 10 minutes load duration factor, C D = 1.6, is applicable to design earthquake loads and design wind loads based on ASCE 7. (e) Load duration factors greater than 1.6 shall not apply to structural members pressure-treated with water-borne preservatives (see Reference 30), or fire retardant chemicals. The impact load duration factor shall not apply to connections. B.2 Combinations of Loads of Different Durations When loads of different durations are applied simultaneously to members which have full lateral support to prevent buckling, the design of structural members and connections shall be based on the critical load combination determined from the following procedures: (a) Determine the magnitude of each load that will occur on a structural member and accumulate subtotals of combinations of these loads. Design loads established by applicable building codes and standards may include load combination factors to adjust for probability of simultaneous occurrence of various loads (see Appendix B.4). Such load combination factors should be included in the load combination subtotals. (b) Divide each subtotal by the load duration factor, C D, for the shortest duration load in the combination of loads under consideration. Shortest Load Duration in the Combination of Loads Load Duration Factor, C D Permanent 0.9 Normal 1.0 Two Months 1.15 Seven Days 1.25 Ten Minutes 1.6 Impact 2.0 (c) The largest value thus obtained indicates the critical load combination to be used in designing the structural member or connection. EXAMPLE: Determine the critical load combination for a structural member subjected to the following loads: D = dead load established by applicable building code or standard

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 159 L = live load established by applicable building code or standard S = snow load established by applicable building code or standard W = wind load established by applicable building code or standard The actual stress due to any combination of the above loads shall be less than or equal to the adjusted design value modified by the load duration factor, C D, for the shortest duration load in that combination of loads: Actual stress due to (C D ) x (Design value) D (0.9) x (design value) D+L (1.0) x (design value) D+W (1.6) x (design value) D+L+S (1.15) x (design value) D+L+W (1.6) x (design value) D+S+W (1.6) x (design value) D+L+S+W (1.6) x (design value) The equations above may be specified by the applicable building code and shall be checked as required. Load combination factors specified by the applicable building code or standard should be included in the above equations, as specified in B.2(a). B.3 Mechanical Connections Load duration factors, C D 1.6, apply to reference design values for connections, except when connection capacity is based on design of metal parts (see 11.2.3). B.4 Load Combination Reduction Factors Reductions in total design load for certain combinations of loads account for the reduced probability of simultaneous occurrence of the various design loads. Load duration factors, C D, account for the relationship between wood strength and time under load. Load duration factors, C D, are independent of load combination reduction factors, and both may be used in design calculations (see 1.4.4). A APPENDIX Figure B1 Load Duration Factors, CD, for Various Load Durations

160 APPENDIX Appendix C C.1 (Non-mandatory) Temperature Effects C.3 As wood is cooled below normal temperatures, its strength increases. When heated, its strength decreases. This temperature effect is immediate and its magnitude varies depending on the moisture content of the wood. Up to 150 F, the immediate effect is reversible. The member will recover essentially all its strength when the temperature is reduced to normal. Prolonged heating to temperatures above 150 F can cause a permanent loss of strength. When wood structural members are heated to temperatures up to 150 F for extended periods of time, adjustment of the reference design values in this Specification may be necessary (see 2.3.3 and 11.3.4). See Reference 53 for additional information concerning the effect of temperature on wood strength. C.2 In some regions, structural members are periodically exposed to fairly elevated temperatures. However, the normal accompanying relative humidity generally is very low and, as a result, wood moisture contents also are low. The immediate effect of the periodic exposure to the elevated temperatures is less pronounced because of this dryness. Also, independently of temperature changes, wood strength properties generally increase with a decrease in moisture content. In recognition of these offsetting factors, it is traditional practice to use the reference design values from this Specification for ordinary temperature fluctuations and occasional shortterm heating to temperatures up to 150 F.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 161 Appendix D D.1 (Non-mandatory) Lateral Stability of Beams D.4 A Slenderness ratios and related equations for adjusting reference bending design values for lateral buckling in 3.3.3 are based on theoretical analyses and beam verification tests. D.2 Treatment of lateral buckling in beams parallels that for columns given in 3.7.1 and Appendix H. Beam stability calculations are based on slenderness ratio, R B, defined as: Reference modulus of elasticity for beam and column stability, E min, in Equation D-3 is based on the following equation: E min = E [1 1.645 COV E ](1.03)/1.66 (D-4) where: E = reference modulus of elasticity 1.03 = adjustment factor to convert E values to a pure bending basis except that the factor is 1.05 for structural glued laminated timber APPENDIX R d (D-1) b e B 2 with e as specified in 3.3.3. D.3 For beams with rectangular cross section where R B does not exceed 50, adjusted bending design values are obtained by the equation (where C L C V ): * * 2 * 1 F * be F b 1 FbE F b FbE Fb F b Fb (D-2) 1.9 1.9 0.95 where: FbE = 1.20 E R min 2 B (D-3) Fb * = reference bending design value multiplied by all applicable adjustment factors except Cfu, CV, and CL (see 2.3) 1.66 = factor of safety COVE = coefficient of variation in modulus of elasticity (see Appendix F) E min represents an approximate 5% lower exclusion value on pure bending modulus of elasticity, plus a 1.66 factor of safety. D.5 For products with less E variability than visually graded sawn lumber, higher critical buckling design values (F be ) may be calculated. For a product having a lower coefficient of variation in modulus of elasticity, use of Equations D-3 and D-4 will provide a 1.66 factor of safety at the 5% lower exclusion value.

162 APPENDIX Appendix E (Non-mandatory) Local Stresses in Fastener Groups E.1 General Where a fastener group is composed of closely spaced fasteners loaded parallel to grain, the capacity of the fastener group may be limited by wood failure at the net section or tear-out around the fasteners caused by local stresses. One method to evaluate member strength for local stresses around fastener groups is outlined in the following procedures. E.1.1 Reference design values for timber rivet connections in Chapter 14 account for local stress effects and do not require further modification by procedures outlined in this Appendix. E.1.2 The capacity of connections with closely spaced, large diameter bolts has been shown to be limited by the capacity of the wood surrounding the connection. Connections with groups of smaller diameter fasteners, such as typical nailed connections in wood-frame construction, may not be limited by wood capacity. E.2 Net Section Tension Capacity The adjusted tension capacity is calculated in accordance with provisions of 3.1.2 and 3.8.1 as follows: Z where: FA (E.2-1) NT t net ZNT = adjusted tension capacity of net section area Ft = adjusted tension design value parallel to grain Anet = net section area per 3.1.2 E.3 Row Tear-Out Capacity The adjusted tear-out capacity of a row of fasteners can be estimated as follows: Z where: FA 2 v critical RTi ni (E.3-1) ZRTi = adjusted row tear out capacity of row i E3.1 Assuming one shear line on each side of bolts in a row (observed in tests of bolted connections), Equation E.3-1 becomes: where: Ft v Z RTi ns i critical2 shear lines (E.3-2) 2 nf ts i v critical scritical = minimum spacing in row i taken as the lesser of the end distance or the spacing between fasteners in row i t = thickness of member The total adjusted row tear-out capacity of multiple rows of fasteners can be estimated as: Z RT where: n row Z (E.3-3) i1 RTi ZRT = adjusted row tear out capacity of multiple rows nrow = number of rows E.3.2 In Equation E.3-1, it is assumed that the induced shear stress varies from a maximum value of f v = F v to a minimum value of f v = 0 along each shear line between fasteners in a row and that the change in shear stress/strain is linear along each shear line. The resulting triangular stress distribution on each shear line between fasteners in a row establishes an apparent shear stress equal to half of the adjusted design shear stress, F v /2, as shown in Equation E.3-1. This assumption is combined with the critical area concept for evaluating stresses in fastener groups and provides good agreement with results from tests of bolted connections. E3.3 Use of the minimum shear area of any fastener in a row for calculation of row tear-out capacity is based on the assumption that the smallest shear area between fasteners in a row will limit the capacity of the row of fasteners. Limited verification of this approach is provided from tests of bolted connections. Fv = adjusted shear design value parallel to grain Acritical = minimum shear area of any fastener in row i ni = number of fasteners in row i

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 163 E.4 Group Tear-Out Capacity The adjusted tear-out capacity of a group of n rows of fasteners can be estimated as: Z where: Z Z FA (E.4-1) 2 2 RT1 RTn GT t group net ZGT = adjusted group tear-out capacity ZRT-1 = adjusted row tear-out capacity of row 1 of fasteners bounding the critical group area ZRT-n = adjusted row tear-out capacity of row n of fasteners bounding the critical group area Agroup-net = critical group net section area between row 1 and row n E.4.1 For groups of fasteners with non-uniform spacing between rows of fasteners various definitions of critical group area should be checked for group tearout in combination with row tear-out to determine the adjusted capacity of the critical section. E.5 Effects of Fastener Placement E.5.1 Modification of fastener placement within a fastener group can be used to increase row tear-out and group tear-out capacity limited by local stresses around the fastener group. Increased spacing between fasteners in a row is one way to increase row tear-out capacity. Increased spacing between rows of fasteners is one way to increase group tear-out capacity. E.5.2 Section 12.5.1.3 limits the spacing between outer rows of fasteners paralleling the member on a single splice plate to 5 inches. This requirement is imposed to limit local stresses resulting from shrinkage of wood members. Where special detailing is used to address shrinkage, such as the use of slotted holes, the 5- inch limit can be adjusted. A APPENDIX E.6 Sample Solution of Staggered Bolts Calculate the net section area tension, row tear-out, and group tear-out ASD adjusted design capacities for the double-shear bolted connection in Figure E1. Main Member: Combination 2 Douglas fir 3-1/8 x 12 glued laminated timber member. See NDS Supplement Table 5B Members stressed primarily in axial tension or compression for reference design values. Adjustment factors C D, C T, and C M are assumed to equal 1.0 and C vr = 0.72 (see NDS 5.3.10) is used in this example for calculation of adjusted design values. F t = 1250 psi F v = 265 psi (C vr ) = 265 (0.72) = 191 psi Main member thickness, t m : 3.125 in. Main member width, w: 12 in. Side Member: A36 steel plates on each side Side plate thickness, t s : 0.25 in. Connection Details: Bolt diameter, D: 1 inch Bolt hole diameter, D h : 1.0625 in. Adjusted ASD bolt design value, Z : 4380 lbs (see Table 12I. For this trial design, the group action factor, C g, is taken as 1.0). Spacing between rows: s row = 2.5D Adjusted ASD Connection Capacity, nz : nz = (8 bolts)(4,380 lbs) = 35,040 lbs Figure E1 Staggered Rows of Bolts

164 APPENDIX Adjusted ASD Net Section Area Tension Capacity, Z NT : Z Ftw n D NT t row h Z NT = (1,250 psi)(3.125")[12" 3(1.0625")] = 34,424 lbs Adjusted ASD Row Tear-Out Capacity, Z RT : Z RT Z nf ts RTi i v critical Z RT-1 = 3(191 psi)(3.125'')(4'') = 7,163 lbs Z RT-2 = 2(191 psi)(3.125'')(4'') = 4,775 lbs Z RT-3 = 3(191 psi)(3.125'')(4'') = 7,163 lbs n row Z RTi = 7,163 + 4,775 + 7,163 = 19,101 lbs i1 Adjusted ASD Group Tear-Out Capacity, Z GT : Z Z Z Ft n 1 s D 2 2 RT1 RT3 GT t row row h Z GT = (7,163 lbs)/2 + (7,163 lbs)/2 + (1,250 psi) (3.125'')[(3 1)(2.5'' 1.0625'')] = 18,393 lbs In this sample calculation, the adjusted ASD connection capacity is limited to 18,393 pounds by group tearout, Z GT. E.7 Sample Solution of Row of Bolts Calculate the net section area tension and row tearout adjusted ASD design capacities for the single-shear single-row bolted connection represented in Figure E2. Main and Side Members: #2 grade Hem-Fir 2x4 lumber. See NDS Supplement Table 4A Visually Graded Dimension Lumber for reference design values. Adjustment factors C D, C T, C M, and C i are assumed to equal 1.0 in this example for calculation of adjusted design values. F t = 525 psi (C F ) = 525(1.5) = 788 psi F v = 150 psi Connection Details: Bolt diameter, D: 1/2 in. Bolt hole diameter, D h : 0.5625 in. Adjusted ASD bolt design value, Z : 550 lbs (See NDS Table 12A. For this trial design, the group action factor, C g, is taken as 1.0). Adjusted ASD Connection Capacity, nz : nz = (3 bolts)(550 lbs) = 1,650 lbs Adjusted ASD Net Section Area Tension Capacity, Z NT : Z Ftw n D NT t row h Z NT = (788 psi)(1.5")[3.5" 1(0.5625")] = 3,470 lbs Figure E2 Single Row of Bolts Adjusted ASD Row Tear-Out Capacity, Z RT : Z nf ts RTi i v critical Z RT1 = 3(150 psi)(1.5")(2") = 1,350 lbs In this sample calculation, the adjusted ASD connection capacity is limited to 1,350 pounds by row tearout, Z RT.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 165 E.8 Sample Solution of Row of Split Rings Calculate the net section area tension and row tear-out adjusted ASD design capacities for the single-shear singlerow split ring connection represented in Figure E3. Main and Side Members: #2 grade Southern Pine 2x4 lumber. See NDS Supplement Table 4B Visually Graded Southern Pine Dimension Lumber for reference design values. Adjustment factors C D, C T, C M, and C i are assumed to equal 1.0 in this example for calculation of adjusted design values. F t = 825 psi F v = 175 psi Main member thickness, t m : 1.5 in. Side member thickness, t s : 1.5 in. Main and side member width, w: 3.5 in. Connection Details: Split ring diameter, D: 2.5 in. (see Appendix K for connector dimensions) Adjusted ASD split ring design value, P: 2,730 lbs (see Table 13.2A. For this trial design, the group action factor, C g, is taken as 1.0). Adjusted ASD Connection Capacity, np: Adjusted ASD Row Tear-Out Capacity, Z RT : Z RTi FA v ni 2 critical Z RT1 = [(2 connectors)(175 psi)/2](21.735 in. 2 ) = 3,804 lbs where: A critical = 21.735 in. 2 (See Figures E4 and E5) In this sample calculation, the adjusted ASD connection capacity is limited to 2,728 pounds by net section area tension capacity, Z NT Figure E4 Acritical for Split Ring Connection (based on distance from end of member) A APPENDIX np = (2 split rings)(2,730 lbs) = 5,460 lbs Adjusted ASD Net Section Area Tension Capacity, Z NT : Z FA NT t net Z NT = F t [A 2x4 A bolt-hole A split ring projected area ] Z NT = (825 psi)[5.25 in. 2 1.5" (0.5625") 1.1 in. 2 ] = 2,728 lbs Figure E3 Single Row of Split Ring Connectors A edge plane = (2 shear lines) (groove depth)(s critical ) = (2 shear lines) (0.375")(5.5") = 4.125 in. 2 A bottom plane net = (A bottom plane ) (A split ring groove ) (A bolt hole ) = [(5.5")(2.92") + ()(2.92") 2 /8] (/4)[(2.92") 2 (2.92" 0.18" 0.18") 2 ] (/4)(0.5625") 2 = 17.61 in. 2 A criticial = A edge plane + A bottom plane net = 21.735 in. 2

166 APPENDIX Figure E5 Acritical for Split Ring Connection (based on distance between first and second split ring) A edge plane = (2 shear lines) (groove depth)(s critical ) = (2 shear lines) (0.375")(6.75") = 5.063 in. 2 A bottom plane net = (A bottom plane ) (A split ring groove ) (A bolt hole ) = (6.75")(2.92") (/4)[(2.92") 2 (2.92" 0.18" 0.18") 2 ] (/4)(0.5625") 2 = 17.91 in. 2 A criticial = A edge plane + A bottom plane net = 5.063 + 17.91 in. 2 = 22.973 in. 2 Therefore A critical is governed by the case shown in Figure E4 and is equal to 21.735 in. 2

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 167 Appendix F (Non-mandatory) Design for Creep and Critical Deflection Applications A F.1 Creep F.1.1 Reference modulus of elasticity design values, E, in this Specification are intended for the calculation of immediate deformation under load. Under sustained loading, wood members exhibit additional time dependent deformation (creep) which usually develops at a slow but persistent rate over long periods of time. Creep rates are greater for members drying under load or exposed to varying temperature and relative humidity conditions than for members in a stable environment and at constant moisture content. F.1.2 In certain bending applications, it may be necessary to limit deflection under long-term loading to specified levels. This can be done by applying an increase factor to the deflection due to long-term load. Total deflection is thus calculated as the immediate deflection due to the long-term component of the design load times the appropriate increase factor, plus the deflection due to the short-term or normal component of the design load. F.2 Variation in Modulus of Elasticity F.2.1 The reference modulus of elasticity design values, E, listed in Tables 4A, 4B, 4C, 4D, 4E, 4F, 5A, 5B, 5C, and 5D (published in the Supplement to this Specification) are average values and individual pieces having values both higher and lower than the averages will occur in all grades. The use of average modulus of elasticity values is customary practice for the design of normal wood structural members and assemblies. Field experience and tests have demonstrated that average values provide an adequate measure of the immediate deflection or deformation of these wood elements. F.2.2 In certain applications where deflection may be critical, such as may occur in closely engineered, innovative structural components or systems, use of a reduced modulus of elasticity value may be deemed appropriate by the designer. The coefficient of variation in Table F1 shall be permitted to be used as a basis for modifying reference modulus of elasticity values listed in Tables 4A, 4B, 4C, 4D, 4E, 4F, 5A, 5B, 5C, and 5D to meet particular end use conditions. F.2.3 Reducing reference average modulus of elasticity design values in this Specification by the product of the average value and 1.0 and 1.65 times the applicable coefficients of variation in Table F1 gives estimates of the level of modulus of elasticity exceeded by 84% and 95%, respectively, of the individual pieces, as specified in the following formulas: E E Table F1 0.16 E E 1 1.0 COV (F-1) 0.05 E E 1 1.645 COV (F-2) Coefficients of Variation in Modulus of Elasticity (COVE) for Lumber and Structural Glued Laminated Timber Visually graded sawn lumber (Tables 4A, 4B, 4D, 4E, and 4F) Machine Evaluated Lumber (MEL) (Table 4C) Machine Stress Rated (MSR) lumber (Table 4C) Structural glued laminated timber (Tables 5A, 5B, 5C, and 5D) COV E 0.25 0.15 0.11 0.10 APPENDIX F.3 Shear Deflection F.3.1 Reference modulus of elasticity design values, E, listed in Tables 4A, 4B, 4C, 4D, 4E, 4F, 5A, 5B, 5C, and 5D are apparent modulus of elasticity values and include a shear deflection component. For sawn lumber, the ratio of shear-free E to reference E is 1.03. For structural glued laminated timber, the ratio of shear-free E to reference E is 1.05. F.3.2 In certain applications use of an adjusted modulus of elasticity to more accurately account for the shear component of the total deflection may be deemed appropriate by the designer. Standard methods for adjusting modulus of elasticity to other load and spandepth conditions are available (see Reference 54). When reference modulus of elasticity values have not been adjusted to include the effects of shear deformation, such as for prefabricated wood I-joists, consideration for the shear component of the total deflection is required. F.3.3 The shear component of the total deflection of a beam is a function of beam geometry, modulus of elasticity, shear modulus, applied load and support conditions. The ratio of shear-free E to apparent E is

168 APPENDIX 1.03 for the condition of a simply supported rectangular beam with uniform load, a span to depth ratio of 21:1, and elastic modulus to shear modulus ratio of 16:1. The ratio of shear-free E to apparent E is 1.05 for a similar beam with a span to depth ratio of 17:1. See Reference 53 for information concerning calculation of beam deflection for other span-depth and load conditions.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 169 Appendix G (Non-mandatory) Effective Column Length G.1 G.3 A The effective column length of a compression member is the distance between two points along its length at which the member is assumed to buckle in the shape of a sine wave. G.2 The effective column length is dependent on the values of end fixity and lateral translation (deflection) associated with the ends of columns and points of lateral support between the ends of column. It is recommended that the effective length of columns be determined in accordance with good engineering practice. Lower values of effective length will be associated with more end fixity and less lateral translation while higher values will be associated with less end fixity and more lateral translation. In lieu of calculating the effective column length from available engineering experience and methodology, the buckling length coefficients, K e, given in Table G1 shall be permitted to be multiplied by the actual column length,, or by the length of column between lateral supports to calculate the effective column length, e. G.4 Where the bending stiffness of the frame itself provides support against buckling, the buckling length coefficient, K e, for an unbraced length of column,, is dependent upon the amount of bending stiffness provided by the other in-plane members entering the connection at each end of the unbraced segment. If the combined stiffness from these members is sufficiently small relative to that of the unbraced column segments, K e could exceed the values given in Table G1. APPENDIX Table G1 Buckling Length Coefficients, K e

170 APPENDIX Appendix H H.1 (Non-mandatory) Lateral Stability of Columns H.3 Solid wood columns can be classified into three length classes, characterized by mode of failure at ultimate load. For short, rectangular columns with a small ratio of length to least cross-sectional dimension, e /d, failure is by crushing. When there is an intermediate e/d ratio, failure is generally a combination of crushing and buckling. At large e /d ratios, long wood columns behave essentially as Euler columns and fail by lateral deflection or buckling. Design of these three length classes are represented by the single column Equation H-1. H.2 For solid columns of rectangular cross section where the slenderness ratio, e /d, does not exceed 50, adjusted compression design values parallel to grain are obtained by the equation: 1F 2 ce F c 1 FcE F c F F F c F 2c 2c c where: * * * * ce c c FcE = 0.822 E /d e min 2 (H-1) (H-2) Fc * = reference compression design value parallel to grain multiplied by all applicable adjustment factors except CP (see 2.3) c = 0.8 for sawn lumber c = 0.85 for round timber poles and piles c = 0.9 for structural glued laminated timber, cross-laminated timber, or structural composite lumber Equation H-2 is derived from the standard Euler equation, with radius of gyration, r, converted to the more convenient least cross-sectional dimension, d, of a rectangular column. The equation for adjusted compression design value, F c ', in this Specification is for columns having rectangular cross sections. It may be used for other column shapes by substituting r 12 for d in the equations, where r is the applicable radius of gyration of the column cross section. H.4 The 0.822 factor in Equation H-2 represents the Euler buckling coefficient for rectangular columns calculated as 2 /12. Modulus of elasticity for beam and column stability, E min, in Equation H-2 represents an approximate 5% lower exclusion value on pure bending modulus of elasticity, plus a 1.66 factor of safety (see Appendix D.4). H.5 Adjusted design values based on Equations H-1 and H-2 are customarily used for most sawn lumber column designs. Where unusual hazard exists, a larger reduction factor may be appropriate. Alternatively, in less critical end use, the designer may elect to use a smaller factor of safety. H.6 For products with less E variability than visually graded sawn lumber, higher critical buckling design values may be calculated. For a product having a lower coefficient of variation (COV E ), use of Equation H-2 will provide a 1.66 factor of safety at the 5% lower exclusion value.

NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION 171 Appendix (Non-mandatory) Yield Limit Equations for Connections A.1 Yield Modes The yield limit equations specified in 12.3.1 for dowel-type fasteners such as bolts, lag screws, wood screws, nails, and spikes represent four primary connection yield modes (see Figure I1). Modes I m and I s represent bearing-dominated yield of the wood fibers in contact with the fastener in either the main or side member(s), respectively. Mode II represents pivoting of the fastener at the shear plane of a single shear connection with localized crushing of wood fibers near the faces of the wood member(s). Modes III m and III s represent fastener yield in bending at one plastic hinge point per shear plane, and bearing-dominated yield of wood fibers in contact with the fastener in either the main or side member(s), respectively. Mode IV represents fastener yield in bending at two plastic hinge points per shear plane, with limited localized crushing of wood fibers near the shear plane(s)..2 Dowel Bearing Strength for Steel Members Dowel bearing strength, F e, for steel members shall be based on accepted steel design practices (see References 39, 40 and 41). Design values in Tables 12B, 12D, 12G, 12I, 12J, 12M, and 12N are for 1/4" ASTM A 36 steel plate or 3 gage and thinner ASTM A 653, Grade 33 steel plate with dowel bearing strength proportional to ultimate tensile strength. Bearing strengths used to calculate connection yield load represent nominal bearing strengths of 2.4 F u and 2.2 F u, respectively (based on design provisions in References 39, 40, and 41 for bearing strength of steel members at connections). To allow proper application of the load duration factor for these connections, the bearing strengths have been divided by 1.6..3 Dowel Bearing Strength for Wood Members Dowel bearing strength, F e, for wood members may be determined in accordance with ASTM D 5764..4 Fastener Bending Yield Strength, Fyb In the absence of published standards which specify fastener strength properties, the designer should contact fastener manufacturers to determine fastener bending yield strength for connection design. ASTM F 1575 provides a standard method for testing bending yield strength of nails. Fastener bending yield strength (F yb ) shall be determined by the 5% diameter (0.05D) offset method of analyzing load-displacement curves developed from fastener bending tests. However, for short, large diameter fasteners for which direct bending tests are impractical, test data from tension tests such as those specified in ASTM F 606 shall be evaluated to estimate F yb. Research indicates that F yb for bolts is approximately equivalent to the average of bolt tensile yield strength and bolt tensile ultimate strength, F yb = F y /2 + F u /2. Based on this approximation, 48,000 psi F yb 140,000 psi for various grades of SAE J429 bolts. Thus, the aforementioned research indicates that F yb = 45,000 psi is reasonable for many commonly available bolts. Tests of limited samples of lag screws indicate that F yb = 45,000 psi is also reasonable for many commonly available lag screws with D 3/8". Tests of a limited sample of box nails and common wire nails from twelve U.S. nail manufacturers indicate that F yb increases with decreasing nail diameter, and may exceed 100,000 psi for very small diameter nails. These tests indicate that the F yb values used in Tables 12N through 12R are reasonable for many commonly available box nails and small diameter common wire nails (D < 0.2"). Design values for large diameter common wire nails (D > 0.2") are based on extrapolated estimates of F yb from the aforementioned limited study. For hardened-steel nails, F yb is assumed to be approximately 30% higher than for the same diameter common wire nails. Design values in Tables 12J through 12M for wood screws and small diameter lag screws (D < 3/8") are based on estimates of F yb for common wire nails of the same diameter. Table I1 provides values of F yb based on fastener type and diameter. APPENDIX

172 APPENDIX Figure 1 (Non-mandatory) Connection Yield Modes